star trek stardate system

Screen Rant

Star trek: how stardates are calculated (& what they really mean).

The stardates used in the Star Trek franchise often seem like a jumble of numbers with no real meaning, but there is some method to the madness.

The stardate system used in the  Star Trek franchise can sometimes feel like a random selection of numbers, but there is some degree of meaning and calculation involved. When first devising and conceptualizing the futuristic world of  Star Trek , Gene Roddenberry decided that the advent of long-range space travel would necessitate a brand new way of measuring time, instead of the standard Gregorian calendar used in the real world. In 1988's  Inside Star Trek documentary, original series researcher, Kellam de Forest, revealed that he took inspiration from the 16th century Julian system, which has been implemented by astronomers ever since. Featuring a way of counting days, ignoring leap years and removing the AD and BC system, the Julian method formed the foundation for  Star Trek 's stardates.

The inspiration for the stardate system may have been simple enough, but applying it to the scripts proved far more complicated, and the exact correlation between  Star Trek  time and real-world time has changed throughout the various TV series and movie iterations. For the original  Star Trek series , the show's bible instructed writers to pick four numbers and a decimal, with the final digit roughly representing a tenth of a day. The example given is that if noon today was 1313.5, noon tomorrow would be 1314.5.

Related: The Odd-Numbered Star Trek Movie Curse Explained (& Is It True)

However, it's important to note that Roddenberry's initial system of dating was intentionally vague, with pilot episode writer, Samuel A. Peeples, revealing that the stardates weren't designed to be decipherable. Roddenberry was initially reluctant to pin  Star Trek  down to a specific time, so the stardate increments were uneven from episode to episode. Unfortunately,  Star Trek encountered a problem when the series first began to air - the network were showing the episodes out of order. This meant that while the stardates were originally supposed to increase as the series progressed, they actually fluctuated wildly. Roddenberry provided an in-narrative explanation for this phenomenon, claiming that stardates took into account the Enterprise 's speed and position in the galaxy, and therefore were relative to both space and time.

This somewhat clunky system was overhauled for  Star Trek: The Next Generation . As well as adding an extra digit,  The Next Generation 's writer's guide reveals that a more structured way of calculating stardates was implemented. The first number indicates the century (4 = 24th), the second number represents the season number (1 = season 1) and the following two digits would be largely random and vary with each episode, much like in the original  Star Trek series. The fifth digit functioned as a day counter, while, as in Roddenberry's original model, the decimal still represented a tenth of a day. This pattern was retained for both  Deep Space Nine and  Star Trek: Voyager .

When J. J. Abrams rebooted the  Star Trek movie series and splintered into the Kelvin timeline , a brand new dating system was introduced that bore a stronger resemblance to the real-world model. As revealed in the revised Star Trek Encyclopedia , the first two digits would represent century (22 = 23rd century), and the second two digits would calculate the year within that century. The 2009 movie also added more numbers after the decimal point, and these would indicate the day of the year. Therefore, 2235.78 would mean the 78th day of the 35th year of the 23rd century.

Beginning with  Star Trek: Discovery , CBS are now in the process of launching a whole new world of content set within the  Star Trek universe that will include  Star Trek: Picard and a Section 31 spinoff . Looking at the stardates used so far in Star Trek: Discovery , it appears that the franchise will come full circle, returning to the stardate system used in  Star Trek: The Original Series . However, with  Star Trek: Discovery  season 2 ending in the far future, the entire stardate system could become redundant when the show returns.

More: Star Trek: Discovery Makes A Bad Original Series Movie Better

Star Trek: Picard  is set to premiere in early 2020 on CBS All Access.

Sources:  Inside Star Trek ,  Gene Roddenberry: The Myth & The Man Behind Star Trek ,  The Making of Star Trek ,  Star Trek Encyclopedia

How Do Star Trek Stardates Work?

By chris higgins | sep 20, 2015.

On Star Trek , we hear a lot of "stardates," meant to mark some futuristic date. An example is stardate 47457.1, which is Captain Picard's birthday . The weird thing is that stardate 47457.1 is either the equivalent June 16th, November 4th, January 8th, or January 10th, depending on how you count. Let's go deep-nerd on this.

The Original Series

In the original Trek TV series, stardates were, in a word, bogus. In the series bible, the Star Trek Guide , writers were basically told to wing it. Here's a snippet (emphasis added):

Pick any combination of four numbers plus a percentage point [ed. note: tenths digit], use it as your story's stardate. For example, 1313.5 is twelve o'clock noon of one day and 1314.5 would be noon of the next day. Each percentage point is roughly equivalent to one-tenth of one day. The progression of stardates in your script should remain constant but don't worry about whether or not there is a progression from other scripts. Stardates are a mathematical formula which varies depending on location in the galaxy, velocity of travel, and other factors, can vary widely from episode to episode.

This obviously wasn't thought through very well, as it boils down to "Pick a number and stay near it." Show creator Gene Roddenberry later said:

When we began making episodes, we would use a stardate such as 2317 one week, and then a week later when we made the next episode we would move the star date up to 2942, and so on. Unfortunately, however, the episodes are not aired in the same order in which we filmed them. So we began to get complaints from the viewers, asking, "How come one week the star date is 2891, the next week it's 2337, and then the week after it's 3414?"

He then went on to explain that the whole "location in the galaxy, velocity of travel, and other factors" thing was a hedge to cover up the fact that the dates simply weren't consistent to begin with, even if the episodes had aired in order.

The Next Generation

In Star Trek: The Next Generation , things got a bit more consistent. In the original TNG Writer's/Director's Guide , the show-runners devised a sensible formula with a reasonable level of continuity. Here it is:

A stardate is a five-digit number followed by a decimal point and one more digit. Example: "41254.7." The first two digits of the stardate are always "41." The 4 stands for 24th century, the 1 indicates first season. The additional three leading digits will progress unevenly during the course of the season from 000 to 999. The digit following the decimal point is generally regarded as a day counter.

It's interesting to note, then, that the duration of a TNG season is 1,000 days. Good thing they were on a continuing mission rather than a five-year one.

Both Star Trek: Deep Space 9 and Star Trek: Voyager continued using the TNG style of Stardates, and the movie Star Trek Nemesis followed suit.

As you might expect, early on in TNG , the writers sometimes goofed. A prime example is Tasha Yar's death, which occurred circa Stardate 41601.3, but she was alive in a previous episode with the (later) Stardate 41997.7. Oops. By 1992, the writers had revised their guidelines to be iron-clad:

A Stardate is a five-digit number followed by a decimal point and one more digit. Example: "46254.7". The first two digits of the Stardate are "46." The 4 stands for the 24th Century, the 6 indicates sixth season. The following three digits will progress consecutively during the course of the season from 000 to 999. The digit following the decimal point counts tenths of a day. Stardate 45254.4, therefore, represents the noon hour on the 254th "day" of the fifth season. Because Stardates in the 24th Century are based on a complex mathematical formula, a precise correlation to Earth-based dating systems is not possible.

Despite explicitly stating that correlation to Earth-based dates is not possible, that hasn't stopped people from trying .

Just when things were basically making sense, they changed again. From an exhaustive and brilliant article on Memory Alpha , here's an explanation of the reboot (J.J. Abrams-directed) movies' treatment of stardates (emphasis added):

The stardate format from the latest film series is credited to screenwriters Roberto Orci and Alex Kurtzman. According to Orci, they "used the system where, for example, 2233.45 or whatever means 23rd century, 33rd year of that century, and the .45 indicates the day of the year out of 365 days." During a Q&A session, Orci restated that a stardate is "the year, as in 2233, with the month and day expressed as a decimal point from .1 to .365 (as in the 365 days of the year)." He posted a similar reply on Twitter: "star date=standard year, with decimal representing day of year from 1-365." The new stardates are similar to the ordinal dates of ISO 8601, which express the first day of 2260 as 2260-001, and the last as 2260-366. Orci hasn't clarified whether leap days increase the count to .366, which would be expected if the years are Gregorian. When asked about 2230.06 and 2233.04 from the Star Trek screenplay, with only one leading zero instead of two or none, he replied that it could have been an error. IDW's Star Trek: Timelines show the latter number as 2233.4.

Long Story Short

There is no one answer to how stardates work, aside from saying that they don't. They're inconsistent series-to-series, and even within a given series, the writers often mixed things up. With Roddenberry trying to retcon the system's continuity even in TOS , perhaps it's appropriate that the system continues to be more than a little mixed up. Time-tracking throughout the galaxy is a hard problem; give 'em some slack.

If you're curious about examples of various Stardates (and even more discussion of this issue), check out Memory Alpha 's stardate page . Trust me, once you've read that, you'll never want to speak of this subject again. If you do, read this page for a deeply unofficial (but supremely logical) system of decimal time. Oh, and don't forget the time the French made a 10-hour day —another attempt to create decimal time that led to total confusion.

Twenty-fourth Century Stardates

Calculating calendar dates in the next generation, deep space nine, and voyager.

While there have been very few references to actual dates in more than 700 episodes of Star Trek , it is possible to derive a fairly accurate correlation between the fictional Stardate system and calendar dates in The Next Generation , Deep Space Nine , and Voyager , based on facts from actual episodes and some calendar math . Facts: Fact: The Next Generation episode "The Neutral Zone," with a Stardate of 41986.0, gave the calendar year as 2364 at the end of the first season . Fact: The Next Generation episode "Data's Day" took place during the Hindu Festival of Lights . The episode aired the week of January 9, 1991 (two and a half years after "The Neutral Zone"), with a Stardate of 44390.1. Fact: Diwali , the five-day Festival of Lights, starts on the New Moon ending the month of Asvina on the Hindu calendar, which typically is the date of the New Moon in India nearest to Halloween. Fact: According to the Calendar Mine 2.0 perpetual calendar, November 3 is the date of the New Moon and the start of Diwali in the year 2366 on Earth. Therefore, the Hindu Festival of Lights would be celebrated in a five-day period starting on November 3, 2366, and ending on November 7, 2366, so Stardate 44390.1 must be within that date span. Fact: The Next Generation episode "Data's Day" also states that Stardate 44390.1 is the 1,550th day since the U.S.S. Enterprise was commissioned. Fact: In The Next Generation episode "All Good Things..." Picard states that he first met Q seven years before Stardate 47988. Their first meeting was depicted on Stardate 41153.7 in "ENCOUNTER AT FARPOINT." Fact: In the Voyager episode "EYE OF THE NEEDLE," Commander Chakotay states that the current year is 2371, with a Stardate of 48579.4. Fact: The Voyager episode "THE 37's" gave the calendar year as 2371 at the beginning of the second season, with a Stardate of 48975.1. Fact: In the Voyager episode "FUTURE'S END," information downloaded from the U.S.S. Voyager 's computer indicates that the Voyager was launched in the year 2371. The first episode of Voyager , "CARETAKER," took place on Stardate 48315.6. Fact: The date for the Voyager episode "11:59" was given as April 22, 2375. (No Stardate was given in the episode, but episodes airing before and after it had Stardates of 52647 and 52861.274.) Fact: The movie STAR TREK: FIRST CONTACT showed that humans made first contact with Vulcans on April 5, 2063. Fact: In the Voyager episode "HOMESTEAD," the crew is celebrating the 315th anniversary of First Contact Day. The following day, a captain's log is recorded on Stardate 54868.6. Fact: An average Earth year comprises about 365.2422 mean solar days. Calculations: Given the above facts, a consistent Stardate system must incorporate the following dates: Stardate 41986.0 must be in the year 2364 ("The Neutral Zone"). Stardate 44390.1 must be between November 3, 2366, and November 7, 2366 ( "Data's Day" ). Stardate 47988 takes place seven years after Stardate 41153.7 ( "ENCOUNTER AT FARPOINT," "All Good Things..." ). Stardate 48315.6 must be in the year 2371 ( "FUTURE'S END," "CARETAKER" ). Stardate 48579.4 must be in the year 2371 ( "EYE OF THE NEEDLE" ). Stardate 48975.1 must be in the year 2371 ( "THE 37's" ). April 22, 2375, takes place between Stardates 52647 and 52861.274 (assuming the episodes before and after "11:59" were in chronological order). Stardate 54868.6 is the day after First Contact Day, the 315th anniversary of April 5, 2063 ( "HOMESTEAD," ). Since The Next Generation episode "Data's Day" and the Voyager episode "HOMESTEAD" both make references to holidays with known dates, these two episodes can be used to establish a Stardate-to-time ratio. However, "Data's Day" (with a Stardate of 44390.1) could take place any time from November 3, 2366, to November 7, 2366, and it is unclear whether "HOMESTEAD" (with a Stardate 54868.6) takes place in the year 2378 or 2377, so that leaves a window of four possible calendar date spans for a definite span of 10478.5 Stardates. (54868.6 - 44390.1 = 10478.5 Stardates) If "Data's Day" took place on November 3, 2366, and "HOMESTEAD" took place on April 6, 2378, then that would give a span of 4,172 days. If "Data's Day" took place on November 7, 2366, and "HOMESTEAD" took place on April 6, 2378, then that would give a span of 4,168 days. If "Data's Day" took place on November 3, 2366, and "HOMESTEAD" took place on April 6, 2377, then that would give a span of 3,807 days. If "Data's Day" took place on November 7, 2366, and "HOMESTEAD" took place on April 6, 2377, then that would give a span of 3,803 days. Given the four possible date spans above, that leaves four possible Stardate-to-time ratios: 4,172 days = 10478.5 Stardates, giving a ratio of 0.39814859 day per Stardate, (4,172 days / 10478.5 Stardates = 0.39814859 day/Stardate) which gives a ratio of 917.351484 Stardates/year . (365.2422 days per year / 0.39814859 day per Stardate = 917.351484 Stardates/year) 4,168 days = 10478.5 Stardates, giving a ratio of 0.397766856 day per Stardate, (4,168 days / 10478.5 Stardates = 0.397766856 day/Stardate) which gives a ratio of 918.23186 Stardates/year . (365.2422 days per year / 0.397766856 day per Stardate = 918.23186 Stardates/year) 3,807 days = 10478.5 Stardates, giving a ratio of 0.36331536 day per Stardate, (3,807 days / 10478.5 Stardates = 0.36331536 day/Stardate) which gives a ratio of 1005.30349 Stardates/year . (365.2422 days per year / 0.36331536 day per Stardate = 1005.30349 Stardates/year) 3,803 days = 10478.5 Stardates, giving a ratio of 0.362933626 day per Stardate, (3,803 days / 10478.5 Stardates = 0.362933626 day/Stardate) which gives a ratio of 1006.36087 Stardates/year . (365.2422 days per year / 0.362933626 day per Stardate = 1006.36087 Stardates/year) If we apply each of the four possible Stardate ratios above to the known fact of the Voyager 's launch date in 2371, then we get the following results: Using the lowest possible Stardate-to-year ratio, 917.351484 Stardates/year , that would mean that the launch of the Voyager on Stardate 48315.6 ( "CARETAKER" ) would be 6553.0 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48315.6 = 6553.0) which would be 2,609.06771 days before April 6, 2378, (0.39814859 day per Stardate x 6553.0 Stardates = 2,609.06771 days) which would mean that "CARETAKER" took place on February 13, 2371. This fits with the fact that the Voyager was launched in 2371 ( "FUTURE'S END" ). Using the second-lowest possible Stardate-to-year ratio, 918.23186 Stardates/year , that would mean that the launch of the Voyager on Stardate 48315.6 ( "CARETAKER" ) would be 6553.0 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48315.6 = 6553.0) which would be 2,606.56621 days before April 6, 2378, (0.397766856 day per Stardate x 6553.0 Stardates = 2,606.56621 days) which would mean that "CARETAKER" took place on February 16, 2371. This fits with the fact that the Voyager was launched in 2371 ( "FUTURE'S END" ). Using the second-highest possible Stardate-to-year ratio, 1005.30349 Stardates/year , that would mean that the launch of the Voyager on Stardate 48315.6 ( "CARETAKER" ) would be 6553.0 Stardates before April 6, 2377 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48315.6 = 6553.0) which would be 2,380.80555 days before April 6, 2377, (0.36331536 day per Stardate x 6553.0 Stardates = 2,380.80555 days) which would mean that "CARETAKER" took place on September 30, 2370. This does not fit with the fact that the Voyager was launched in 2371 ( "FUTURE'S END" ). Using the highest possible Stardate-to-year ratio, 1006.36087 Stardates/year , that would mean that the launch of the Voyager on Stardate 48315.6 ( "CARETAKER" ) would be 6553.0 Stardates before April 6, 2377 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48315.6 = 6553.0) which would be 2,378.30405 days before April 6, 2377, (0.362933626 day per Stardate x 6553.0 Stardates = 2,378.30405 days) which would mean that "CARETAKER" took place on October 2, 2370. This does not fit with the fact that the Voyager was launched in 2371 ( "FUTURE'S END" ). Given the above results, we can discard possibilities 3 and 4, since they do not fit with a Voyager launch date of 2371. Since these were the only two options in which the episode "HOMESTEAD" took place in 2377, then we can conclude that "HOMESTEAD" must have taken place in April 2378, the 315th anniversary of first contact with Vulcans on April 5, 2063 ( STAR TREK: FIRST CONTACT ). (2063 + 315 = 2378) Having proven that "HOMESTEAD" must have taken place in April 2378, then that means that the only possible Stardate-to-year ratios are between 917.351484 Stardates/year and 918.23186 Stardates/year . If we apply each of these ratios to the fact that Stardate 48975.1 must be in the year 2371 ( "THE 37's" ), we get the following results: Using the lowest possible Stardate-to-year ratio, 917.351484 Stardates/year , that would mean that "THE 37's" (on Stardate 48975.1) would be 5893.5 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48975.1 = 5893.5) which would be 2,346.48872 days before April 6, 2378, (0.39814859 day per Stardate x 5893.5 Stardates = 2,346.48872 days) which would mean that "THE 37's" took place on November 3, 2371. This fits with the stated year of 2371 in "THE 37's" . Using the highest possible Stardate-to-year ratio, 918.23186 Stardates/year , that would mean that "THE 37's" (on Stardate 48975.1) would be 5893.5 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 48975.1 = 5893.5) which would be 2,344.23897 days before April 6, 2378, (0.397766856 day per Stardate x 5893.5 Stardates = 2,344.23897 days) which would mean that "THE 37's" took place on November 5, 2371. This fits with the stated year of 2371 in "THE 37's" . If we apply each of the above ratios to the fact that Stardate 41986.0 must be in the year 2364 ("The Neutral Zone"), we get the following results: Using the lowest possible Stardate-to-year ratio, 917.351484 Stardates/year , that would mean that TNG episode "The Neutral Zone" (on Stardate 41986.0) would be 12882.6 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 41986.0 = 12882.6) which would be 5,129.18903 days before April 6, 2378, (0.39814859 day per Stardate x 12882.6 Stardates = 5,129.18903 days) which would mean that "The Neutral Zone" took place on March 21, 2364. This fits with the stated year of 2364 in "The Neutral Zone." Using the highest possible Stardate-to-year ratio, 918.23186 Stardates/year ,that would mean that TNG episode "The Neutral Zone" (on Stardate 41986.0) would be 12882.6 Stardates before April 6, 2378 ( "HOMESTEAD" ), which had a Stardate of 54868.6, (54868.6 - 41986.0 = 12882.6) which would be 5,124.2713 days before April 6, 2378, (0.397766856 day per Stardate x 12882.6 Stardates = 5,124.2713 days) which would mean that "The Neutral Zone" took place on March 26, 2364. This fits with the stated year of 2364 in "The Neutral Zone." Conclusions: Given the above facts and calculations , we can conclude that: The Voyager episode "HOMESTEAD" (Stardate 54868.6) must have taken place on April 6, 2378. The highest possible Stardate-to-year ratio is 918.23186 Stardates per year (or 0.397766856 day to 1.0 Stardate , or 1.0 Stardate to 34,367.0564 seconds ). With the two above conclusions, it is possible to calculate a calendar date for any Stardate given in The Next Generation , Deep Space Nine , and Voyager . Given the date of Voyager episode "HOMESTEAD" (Stardate 54868.6) and a ratio of 918.23186 Stardates per year, it is now possible to calculate the starting point of The Next Generation Stardate system, i.e., Stardate 00000.0. Stardate 00000.0 would be 54868.6 Stardates before April 6, 2378 ( "HOMESTEAD" ), which, given the Stardate-to-year ratio established above, would be 21,824.9105 days before April 6, 2378. (0.397766856 day/Stardate x 54868.6 Stardates = 21,824.9105 days) Subtracting 21,824 days, 1,311 minutes, from April 6, 2378, calculates to Friday, July 5, 2318, around noon. So we can conclude that Stardate 00000.0 started on Friday, July 5, 2318 , around noon (Starfleet Command time).

Twenty-third Century Stardates

Calculating calendar dates in the original series.

During the run of The Original Series , there were few references to dates, nor even to the century in which the series took place. Furthermore, the Stardates used in The Original Series had a different starting point than The Next Generation Stardates, so it is impossible to directly extrapolate dates backwards from The Next Generation . However, there were sufficient references in The Next Generation to retroactively calculate dates in The Original Series , with a few additional Stardate facts from episodes of The Original Series , The Next Generation , and Voyager . Facts: Fact: In The Next Generation episode "Sarek," Captain Picard states that Ambassador Sarek is 202 years old. The episode takes place on Stardate 43917.4, which, according to the above calculations , would take place on Tuesday, May 3, 2366. Thus, for Picard's statement to be true on that date, Sarek would have been born between May 4, 2163 and May 3, 2164. Fact: In The Original Series episode "JOURNEY TO BABEL," Ambassador Sarek states that he is precisely 102.437 Earth years old on Stardate 3842.4. Based on the above range determined for the date of Sarek's birth, "JOURNEY TO BABEL" must have taken place between October 11, 2265, and October 9, 2266. Fact: The American Thanksgiving holiday typically is celebrated on the fourth Thursday of November. Fact: In The Original Series episode "CHARLIE X," the crew of the U.S.S. Enterprise is celebrating Thanksgiving. The given Stardates for this episode were 1533.6 and 1533.7. This is 2308.7 Stardates before Stardate 3842.4 in the episode "JOURNEY TO BABEL," which was determined above to have taken place between October 11, 2265, and October 9, 2266. (3842.4 - 1533.7 = 2308.7 Stardates) Fact: Captain Kirk's monologue in the opening titles of The Original Series established that the crew was on a five-year mission. The earliest Stardate in The Original Series was 1312.4 in "WHERE NO MAN HAS GONE BEFORE," and the latest Stardate was 5943.7 in "ALL OUR YESTERDAYS," a difference of 4631.3 Stardates. (5943.7 - 1312.4 = 4631.3 Stardates) Fact: If episodes of The Animated Series are also considered part of the original five-year mission, then the earliest Stardate was 1254.4 in the animated episode "THE MAGICKS OF MEGAS-TU," and the latest Stardate was 7403.6 in the animated episode "BEM," a difference of 6149.2 Stardates. (7403.6 - 1254.4 = 6149.2 Stardates) Fact: In the Voyager episode "Q2," Icheb states that Kirk completed his historic five-year mission in 2270. Therefore, all episodes of The Original Series must have taken place after January 1, 2265 (assuming it was exactly five years), and before January 1, 2271. Fact: In the episode "DAGGER OF THE MIND," on Stardate 2715.1, Dr. Helen Noel said she met Captain Kirk at the Science Lab Christmas party. Fact: Christmas is traditionally celebrated on December 25, and office Christmas parties are typically celebrated sometime in December. Given the possible date range for the five-year mission established in "Q2," the Christmas party referred to in "DAGGER OF THE MIND" must have taken place between December 2265 and December 2270. Calculations: Thanksgiving in "CHARLIE X" took place before the episode "JOURNEY TO BABEL" -- which, as determined above, took place between October 11, 2265, and October 9, 2266 -- and Thanksgiving in "CHARLIE X" must have taken place after January 1, 2265, given the end date of the five-year mission in "Q2." Therefore, the only possible date for "CHARLIE X" would be November 23, 2265 (which is the fourth Thursday of the month, according to the perpetual calendar ). If the Christmas party referred to in "DAGGER OF THE MIND" is assumed to be the same year as Thanksgiving in "CHARLIE X," then there would be at least a month between the two episodes, a difference of 1181.4 Stardates (giving a ratio of less than 1,000 Stardates per month). If the Christmas party were the following year, then the difference of 1181.4 Stardates would span at least a year (which would give a ratio of at least 1,000 Stardates per year). The Christmas party referred to could not be from the year before Thanksgiving in "CHARLIE X," since the possible date range for the five-year mission established in "Q2" dictates that the five-year mission did not begin before 2265. Having calculated above that Stardate 1533.7 is on November 23, 2265 ( "CHARLIE X," ), and that Stardate 3842.4 ( "JOURNEY TO BABEL" ) must be between October 11, 2265, and October 9, 2266, the maximum span between Stardates 1533.7 and 3842.4 (a difference of 2308.7 Stardates) can be no more than 320 days (or 0.876130962 year). Therefore, there must be at least 2635.10833 Stardates per year (or at least 7.21468749 Stardates per day). (2308.7 Stardates / 0.876130962 year = 2635.10833 Stardates/year) This means that Stardate 0000.0 -- 1533.7 Stardates before November 23, 2265, in "CHARLIE X" -- must have started 0.582025408 year (212.58024 days) before that episode. (1533.7 Stardates / 2635.10833 Stardates/year = 0.582025408 year) So, assuming the lowest possible Stardate-to-year ratio of 2635.10833 Stardates per year, Stardate 0000.0 began on Tuesday, April 25, 2265, at 00:00 hours. (November 23, 2265 - 212.58024 days = April 25, 2265) Conclusions: Given the above facts and calculations , we can conclude that: Stardate 0000.0 began on Tuesday, April 25, 2265, at 00:00 hours. The lowest possible Stardate-to-year ratio is 2635.10833 Stardates per year (at least 7.21468749 Stardates per day , or less than 0.138606142 day per Stardate ). Therefore, in The Original Series , one Stardate is no more than 11,975,570.7 milliseconds (0.138606142 day = 11,975,570.7 milliseconds) Given the above starting point and the assumed ratio of 2635.10833 Stardates per year, it is possible to calculate the calendar date for any episode in The Original Series . For example, "DAGGER OF THE MIND," on Stardate 2715.1, would have taken place on May 6, 2266, just a few months after the Christmas party referred to in the episode. So the earliest Stardate in The Original Series -- 1312.4 in "WHERE NO MAN HAS GONE BEFORE" -- took place on October 23, 2265, and the latest Stardate -- 5943.7 in "ALL OUR YESTERDAYS" -- was on July 27, 2267. (The earliest Stardate in The Animated Series -- 1254.4 in "THE MAGICKS OF MEGAS-TU" -- would have taken place on October 15, 2265, and the latest Stardate -- 7403.6 in "BEM" -- would have taken place on February 15, 2268.)

Late Twenty-third Century Stardates

Calculating calendar dates in the movie series.

The first six Star Trek motion pictures continued the pattern of four-digit Stardates from The Original Series . However, it is clear that it is not a simple linear continuation of the same Stardate system. Therefore, either the time ratio of The Original Series Stardates changed mid-way through the original five-year mission and continued through the movies, or else the motion pictures use another Stardate system with a completely new starting point and different time ratio from The Original Series Stardates. Facts: Fact: In STAR TREK: THE MOTION PICTURE , on Stardate 7410.2, Admiral James Kirk has been Chief of Starfleet Operations for the past two and a half years, and hasn't logged a single star hour in that time, since completing his five-year mission. So, based on the end date of the five-year mission established in "Q2," Stardate 7410.2 must be at least two and a half years after January 1, 2270. Fact: Since STAR TREK: THE MOTION PICTURE , on Stardate 7410.2, takes place two and a half years after Captain Kirk's original five-year mission ended, then it must be at least two and a half years after the latest Stardate in The Original Series -- 5943.7 in "ALL OUR YESTERDAYS" -- a difference of 1466.5 Stardates. (7410.2 - 5943.7 = 1466.5 Stardates) Fact: If episodes of The Animated Series are also considered part of the original five-year mission, then STAR TREK: THE MOTION PICTURE , on Stardate 7410.2, must take place at least two and a half years after the latest Stardate -- 7403.6 in the animated episode "BEM" -- a difference of 0006.6 Stardates. (7410.2 - 7403.6 = 0006.6 Stardates) Fact: In STAR TREK: THE MOTION PICTURE , on Stardate 7410.2, V'ger is less than three days away from Earth. On Stardate 7414.1, V'ger reaches Earth, so a span of 0003.9 Stardates must be less than three days. (7414.1 - 7410.2 = 0003.9 Stardates) Fact: In STAR TREK II: THE WRATH OF KHAN , the Project Genesis video proposal was recorded by Dr. Carol Marcus on Stardate 7130.4. After Stardate 8130.4, Admiral Kirk states that the tape was made "about a year ago." Fact: In STAR TREK II: THE WRATH OF KHAN , on Stardate 8130.4, Khan has been stranded on Ceti Alpha Five for 15 years, since Stardate 3143.3 in the episode "SPACE SEED" -- which, according to The Original Series Stardate calculations above, would have taken place on July 4, 2266. Therefore, Stardate 8130.4 must take place after July 4, 2281 (assuming Khan is talking about Earth years and not Ceti Alpha Five years). Fact: In STAR TREK II: THE WRATH OF KHAN , on Stardate 8130.3, Dr. McCoy gives Admiral Kirk a bottle of Romulan Ale (vintage 2283) for his birthday. Therefore, Stardate 8130.3 must take place after 2283 (assuming 2283 is an Earth year, and not a Romulan year or a Stardate). Fact: In STAR TREK III: THE SEARCH FOR SPOCK , around Stardate 8210.3, Starfleet Commander Morrow states that the U.S.S. Enterprise is twenty years old. An officer later refers to Uhura as a twenty-year space veteran. Fact: In STAR TREK III: THE SEARCH FOR SPOCK , the U.S.S. Enterprise flight recorder shows that Spock was dying from radiation poisoning after escaping the Genesis Device detonation on Stardate 8128.78. On Stardate 8128.77, Spock had just been exposed to radiation. Stardates 8128.76.00 to 8128.76.32 spanned a few seconds in which Spock performed a mind-meld with Dr. McCoy before entering the irradiated Engineering chamber. Fact: In STAR TREK IV: THE VOYAGE HOME , on Stardate 8390, the U.S.S. Enterprise crew has been on Vulcan for three months (since just after Stardate 8210.3 in STAR TREK III: THE SEARCH FOR SPOCK ). Therefore, a span of 179.7 Stardates represents at least three months (8390 - 8210.3 = 179.7 Stardates) , so 718.8 Stardates would span at least 12 months (179.7 Stardates/3 months x 4/4 = 718.8 Stardates/12 months) . Fact: In STAR TREK V: THE FINAL FRONTIER , on Stardate 8454.1, the U.S.S. Enterprise NCC-1701-A has been under repairs for at least three weeks. The starship was first seen sometime after Stardate 8390 in STAR TREK IV: THE VOYAGE HOME , so there must be at least a month in the span of 64.1 Stardates (8454.1 - 8390 = 64.1 Stardates) ; therefore, there must be at least a year in a span of 769.2 Stardates (64.1 Stardates x 12 = 769.2 Stardates) . Fact: In STAR TREK VI: The Undiscovered Country , on Stardate 9521.6, the U.S.S. Excelsior detected the destruction of the Klingon moon Praxis, three years after Captain Sulu took command. Two months later, Starfleet Command sends the U.S.S. Enterprise on a diplomatic mission, and Captain Kirk records a log entry on Stardate 9522.6. A few days later, Captain Kirk records his final log entry on Stardate 9529.1. Therefore, a span of 1.0 Stardate is at least two months. (9522.6 - 9521.6 = 1.0 Stardate) . Fact: In STAR TREK VI: The Undiscovered Country , after Stardate 9522.6, McCoy states that he has been ship's surgeon aboard the U.S.S. Enterprise for 27 years. Fact: In the Voyager episode "FLASHBACK," after Stardate 50126.4, Tuvok states that his first deep space assignment aboard the U.S.S. Excelsior , on Stardate 9521, was approximately 80 years ago, when he was 29 years old. Given the assumed date of Tuvok's birth on October 14, 2266, then Stardate 9521 must be at least 29 years after October 14, 2266. However, this conflicts with McCoy's statement that he has been aboard the U.S.S. Enterprise for only 27 years, since his earliest appearance, on Stardate 1512.2 in "THE CORBOMITE MANEUVER," was almost a year before Tuvok's birth .

Star Trek XI-XII Stardates

Calculating calendar dates in the latest movie.

Fact: In STAR TREK , on Stardate 2258.42, Ambassador Spock states that Stardate 2387 is about 129 years in the future, and Stardate 2233.04 is about 25 years in the past. (2387 - 2258.42 = 128.58 Stardates) , (2258.42 - 2233.04 = 25.38 Stardates) . Fact: An average Earth year comprises about 365.2422 mean solar days. Therefore, each 100th of a year would be 3.652422 days. (1 year / 100 = 365.2422 days / 100 = 3.652422 days) . Fact: In STAR TREK INTO DARKNESS , Stardate 2259.55 is approximately one year later than the events in the previous movie (whose Stardate was 2258.42). . Conclusion: The new STAR TREK film appears to use a ratio of one Stardate per year; more specifically, the Stardates in the film are consistent with the actual Earth calendar years expressed with two decimal places (presumably representing hundredths of the calendar year). These new Stardates are used to express calendar dates both before The Original Series Stardates and after The Next Generation Stardates . Using this information, and the above TNG Stardate Calculator and TOS Stardate Calculator , these new Stardates can be compared with calendar dates from both The Original Series and The Next Generation . For example, Ambassador Spock's given Stardate of 2387 in STAR TREK would take place about eight years after the latest known TNG Stardate in STAR TREK: NEMESIS , whose given Stardate of 56844.9 would be around March 29, 2379, according to the above TNG Stardate Calculator . Also, the given Stardate of 2258.42 in STAR TREK , when James Kirk is around 25 years old, would take place about seven years before the earliest Stardate in The Original Series , 1312.4 in "WHERE NO MAN HAS GONE BEFORE," which would be around October 24, 2265, according to the above TOS Stardate Calculator . Kirk's birth on Stardate 2233.04 depicted in STAR TREK would be around January 15, 2233 , assuming Stardate 2233.00 corresponds with 00:00 hours on January 1, 2233. (00:00 January 1, 2233 + 0.04 x 365.2422 days = 00:00 January 1, 2233 + 14.609688 days) . Given Kirk's birth date of January 15, 2233 (assuming his birth date in the alternate universe depicted in STAR TREK was the same as, or close to, his birth date in The Original Series ), his exact age can now be calculated for any Stardate given in an episode of The Original Series . In addition, in STAR TREK II: THE WRATH OF KHAN , Admiral Kirk is celebrating his birthday on Stardate 8130.3 when Dr. McCoy gives him a bottle of Romulan Ale (vintage 2283). Therefore, Stardate 8130.3 (in The Movie Series Stardate system ) must take place around January 15 in some year after 2283 (or a few weeks after January 15, if it is assumed that the alternate events depicted in STAR TREK caused Kirk to be born prematurely).

Date inconsistencies in episodes

While the episodes and assumptions cited above present a fairly accurate and consistent theory for calculating Stardates, there are many other date references -- mostly vague references to years -- that conflict with that theory, though these exceptions do not clearly establish a more-consistent alternative theory, so they may be regarded as errors. Stardate-to-year ratios: In The Original Series episode "THE CORBOMITE MANEUVER" , the span between Stardate 1512.2 and Stardate 1513.8 is described as "18 hours." That is a difference of 1.6 Stardate units (1513.8 - 1512.2 = 1.6 Stardates) . If 1.6 Stardates are 18 hours, then 1 Stardate would equal 11.25 hours (18 hours / 1.6 Stardates = 11.25 hours/Stardate) , and 2.13333333333 Stardates would be one day (24 hours/day / 11.25 hours/Stardate = 2.13333333333 Stardates/day) , so 779.18336 Stardates would be about a year (2.13333333333 Stardates/day x 365.2422 days/year = 779.18336 Stardates/year) . Given the above calculations that there must be at least 2635.10833 Stardates per year (or at least 7.21468749 Stardates per day), the Stardates and hours stated in "THE CORBOMITE MANEUVER" are inconsistent with the overall progression of Stardates in The Original Series . In The Original Series episode "THE GAMESTERS OF TRISKELION" , the span between Stardate 3211.8 and Stardate 3259.2 is described as "nearly two hours." That is a difference of 47.4 Stardate units (3259.2 - 3211.8 = 47.4 Stardates) . If 47.4 Stardates are nearly two hours, then 568.8 Stardates would be nearly a day (47.4 Stardates/2 hours x 24 hours/day = 568.8 Stardates/day ) , and 207,749.76 Stardates would be nearly a year (568.8 Stardates/day x 365.2422 days/year = 207749.76 Stardates/year) . This is inconsistent with the slow progression of four-digit Stardates throughout The Original Series , demonstrating that Stardate spans shown within single episodes cannot be extrapolated to measure Stardates across multiple episodes. In The Next Generation episode " Pen Pals ," the Enterprise enters the Selcundi Drema Sector on Stardate 42695.3. On Stardate 42696.3, Lieutenant Commander Data picks up an alien radio signal. On Stardate 42737.3, Captain Picard states that it has been six weeks since the Enterprise entered the Selcundi Drema Sector. Shortly before Stardate 42741.3, Data says he picked up the alien transmission eight weeks ago. So there is a span of 42.0 Stardates in six weeks (42737.3 - 42695.3 = 42.0 Stardates) , for a ratio of about 7.0 Stardates per week, and a span of 45.0 Stardates in at least eight weeks (42741.3 - 42696.3 = 45.0 Stardates) , for a ratio of 5.625 Stardates per week. These ratios would extrapolate to about 1 Stardate per day, or between 292 and 365 Stardates per year . In The Next Generation episode "The Best of Both Worlds" Part II ," the battle between Starfleet and the Borg at Wolf 359 starts after Stardate 44001.4. and shortly before Stardate 44002.3. In the Deep Space Nine episode "EMISSARY," it was stated that Captain Picard was kidnapped by the Borg on Stardate 43997 for six days, during which he led an assault on Starfleet at Wolf 359, resulting in the death of Jennifer Sisko. Three years later, on Stardate 46379.1, Commander Sisko is reassigned to station Deep Space Nine in orbit of Bajor. So there is a span of about 2376.8 Stardates in three years (46379.1 - 44002.3 = 2376.8 Stardates) , for a ratio of about 792.266666667 Stardates per year (2376.8 Stardates / 3 years = 792.266666667 Stardates/year) . In the Deep Space Nine episode "SECOND SIGHT," on Stardate 47329.4, Commander Sisko records a personal log stating that the previous day was the fourth anniversary of the massacre at Wolf 359 and the death of Jennifer Sisko. So there is a span of about 3327.1 Stardates in four years (47329.4 - 44002.3 = 3327.1 Stardates) , for a ratio of about 831.775 Stardates per year (3327.1 Stardates / 4 years = 831.775 Stardates/year) . (It is unclear whether Sisko is describing Earth years or Bajoran years, since he is on a Bajoran station with 26 hours per day.) In the Voyager episode "RELATIVITY" , Seven of Nine states on Stardate 49123.5621 that the Voyager will be destroyed in three years, six months and two days, on Stardate 52861.274 -- a difference of 3737.7119 Stardates. This is a span of 1,280 to 1,282 days (3.504522888 to 3.509998705 years), depending on leap years and lengths of different months, giving a ratio of around 1,065 Stardates per year . In the Voyager episode "TIMELESS," Captain Janeway states that the Voyager has been in the Delta Quadrant for four years, two months, and 11 days. The following morning, around 08:00 hours, she records a log entry on Stardate 52143.6. In the Voyager episode "CARETAKER," the Voyager was brought to the Delta Quadrant three days before Stardate 48315.6 -- a difference of 3828.0 Stardates before "TIMELESS." Therefore, there is a span of 1,531 days (4.191737923 years) in a span of 3828.0 Stardates, giving a ratio of 913.225 Stardates per year . Between Day 65 and Day 70 of the Voyager episode "YEAR OF HELL," a captain's log was recorded on Stardate 51268.4 (May 5, 2374, according to the above calculations ), and Chakotay later mentions that it is May 20 (Captain Janeway's birthday). In "YEAR OF HELL, PART II," on Day 133 a captain's log is recorded on Stardate 51425.4 (July 6, 2374, according to the above calculations ). Between Day 207 and Day 257, Janeway mentions her birthday was "five months ago;" she later records a captain's log on Stardate 51682.2 (October 16, 2374, according to the above calculations ). On Day 1 after the timeline is restored, a captain's log is recorded on Stardate 51252.3 (April 28, 2374, according to the above calculations ). Therefore, there is a span of 16.1 Stardates in the first 64 days of the "YEAR OF HELL" (51268.4 - 51252.3 = 16.1 Stardates) , giving a ratio of 0.2515625 Stardate per day (16.1 Stardates / 64 days = 0.2515625 Stardate/day) , or 91.88 Stardates per year . The captain's log recorded between Day 207 and Day 257 would be 429.9 Stardates after Day 1 (51682.2 - 51252.3 = 429.9 Stardates) and at least "five months" or 413.8 Stardates after Day 65 (51682.2 - 51268.4 = 413.8 Stardates) . These date spans give a possible ratio of around 700 to 1,000 Stardates per year . The captain's log recorded on Stardate 51425.4 on Day 133 would be 173.1 Stardates after Stardate 51252.3 on Day 1 (51425.4 - 51252.3 = 173.1 Stardates) , giving a span of 173.1 Stardates in 132 days, or a ratio of 1.3113636364 Stardates per day (173.1 Stardates / 132 days = 1.3113636364 Stardates/day) , or 478.96533956 Stardates per year . In The Next Generation episode "The Naked Now," Data first uses his sexual techniques just after Stardate 41209.3 (May 22, 2363, according to the above calculations ). In STAR TREK: FIRST CONTACT , a couple days after Stardate 50893.5 (December 7, 2373, according to the above calculations ), Data states that he last used his programming in sexual techniques eight years, seven months, sixteen days, four minutes, twenty-two seconds ago (which, according to the date calculator , would be a couple days after April 21, 2365, or after Stardate 42973, according to the above calculations ; this would place Data's last use of his programming in sexual techniques between the last two episodes in The Next Generation 's second season ). However, if Data used his programming in sexual techniques only twice -- in "The Naked Now" and STAR TREK: FIRST CONTACT -- then the span of "eight years, seven months, sixteen days, four minutes, twenty-two seconds" (or 272,333,062 seconds) would be a little more than the span between Stardates 41209.3 and 50893.5 (9684.2 Stardates), giving a ratio of less than 9684.2 Stardates per 272,333,062 seconds (or 8.62989831 years), or less than 1122.16849517 Stardates per year . ( 9684.2 Stardates / 8.62989831 years = 1122.16849517 Stardates/year) (50893.5 - 41209.3 = 9684.2 Stardates) . That gives a ratio of more than 1122.5 Stardates per year (9684.2 Stardates / 8.6274 years = 1122.5 Stardates/year) . From and including: Wednesday, April 21, 2365 at 4:52:02 AM To, but not including : Friday, December 7, 2373 at 4:56:24 AM The duration is 3152 days, 0 hours, 4 minutes and 22 seconds Or 8 years, 7 months, 16 days, 4 minutes, 22 seconds Alternative time units 3152 days, 0 hours, 4 minutes and 22 seconds can be converted to one of these units: 272,333,062 seconds 4,538,884 minutes (rounded down) 75,648 hours (rounded down) 450 weeks (rounded down) From date: Friday, December 7, 2373 at 4:56:24 AM Subtracted 8 years, 7 months, 16 days, 4 minutes, 22 seconds Resulting date: Wednesday, April 21, 2365 at 4:52:02 AM (last used) May 22 2363 (first used) --> Given the wild inconsistencies of Stardate ratios in different episodes, some varying by a factor of ten, there can be no conclusive determination of an actual Stardate-to-year ratio for all episodes. Therefore, the ratio of 918.23186 Stardates per year , as calculated above , will remain the basic assumption upon which the above TNG Stardate Calculator is based. Tuvok's Birthday In the Voyager episode "EX POST FACTO," it is stated that Tuvok has been married for 67 years. In the Voyager episode "FLASHBACK," after Stardate 50126.4, Tuvok states that his first deep space assignment aboard the U.S.S. Excelsior , on Stardate 9521, was approximately 80 years ago, when he was 29 years old. In the episode "UNIMATRIX ZERO" PART II , it is stated that Tuvok was born on Vulcanis Lunar Colony on Stardate 38774. This last reference is clearly an error, since Stardate 38774 in The Next Generation system would be just three years before "The Neutral Zone" (41986.0), which gave the year as 2364 -- meaning Tuvok would be just 10 years old in Voyager 's first episode on Stardate 48315.6. It is likely that the decimal was left out of Tuvok's given birth date, and he was really born on Stardate 3877.4 (October 14, 2266, based on the above calculations ) in The Original Series Stardate system. This would place his birth just after The Original Series episode "JOURNEY TO BABEL" , which had a Stardate of 3842.3. Given a birth date of October 14, 2266, Tuvok would be about 106 years old on Stardate 50126.4 in "FLASHBACK," which would be on February 5, 2373, according to the above Stardate Calculator . As stated in "FLASHBACK," Tuvok was 29 years old on Stardate 9521, meaning that STAR TREK VI: The Undiscovered Country must have taken place within the year following October 14, 2295. However, in the episode "FURY," Captain Janeway celebrates Tuvok's birthday, stating it is not long before he reaches "the big three digits." The episode had no Stardate, but the episode before it took place on Stardate 53918, which would place it in the middle of 2377 (based on the above calculations ). If the statement "the big three digits" is taken to mean "100 Earth years," then this would mean that Tuvok would be born after 2277, making him 11 years younger than assumed above. But if "the big three digits" is taken to mean "111 Earth years" (three identical digits), that would be consistent with the above assumptions, since Tuvok would be born on October 14, 2266 (TOS Stardate 3877.4), making him 111 years old on October 14, 2377. This could mean that "FURY," (which had no Stardate) might be shown out of order, and actually took place on Tuvok's 110th birthday, October 14, 2376. (Of course, it is unclear whether Janeway's statement even refers to Earth years rather than Vulcan years, so the statement may not be inconsistent after all, since the duration of a Vulcan year has not been established.) In the Enterprise episode "AWAKENING," Minister Kuvak of the Vulcan High Command states that Earth and Vulcan have been allies for 100 years. The episode takes place in the middle of the year 2154, and apparently refers to first contact between Earth and Vulcans on April 5, 2063, a span of more than 91 Earth years. Since Vulcans are known to quote numbers with great precision, and the statement about 100 years was made between two Vulcans on the planet Vulcan with no humans present, it would be reasonable to assume they were describing the time span in Vulcan years. If so, then 100 Vulcan years is about 91 Earth years, so one Vulcan year would be about 0.91 Earth year. Therefore, Tuvok's age of 111 Earth years would be equivalent to about 121 Vulcan years, making Janeway's statement in "FURY" about him soon reaching "the big three digits" inaccurate in both Earth and Vulcan years.

How Do Star Trek Stardates Actually Work?

T here are few handier delivery mechanisms for "Star Trek" exposition than a Captain's log entry, crucial Starfleet records that mark time with "stardates" — an enigmatic calendar system integrating decimals into each date. Although based on a real-world astronomical dating system, the Starfleet version doesn't make a ton of sense because it was never meant to, which is why  the "Star Trek" timeline can seem confusing  the deeper you dig into it.

As outlined in a  1967 "Star Trek" writer and director's guide, "The progression of stardates in your script should remain constant but don't worry about whether or not there is a progression from other scripts." Still, understanding the Julian date system can be a good starting point for those who care to try.

Speaking with The Space Review  in 2019, "Star Trek: The Original Series" technical advisor Kellam de Forest explained that the futuristic calendar system was inspired by the Julian day — the solar day measurement used in the 365-day Julian solar dating system that predated the Gregorian calendar. Because the Julian day system creates a continued count of dates from the beginning of the Julian period, the ease of calculation between two dates without breaks has made it the preferred calendar for many scientific applications, including astronomical software. Julian dates are calculated by adding the Julian day — that is, the solar day since the beginning of the Julian calendar — and then adding a decimal point to indicate the fraction of the day that has passed since noon in Universal Time Code (UTC). Although the Julian date calculates days running into the millions, only the final five digits are commonly used by astronomers — and just four are used in "Star Trek."

Read more: Star Trek Stories That Are Actually Horrifying

Stardates Are Intentionally Difficult To Calculate

According to the "Star Trek" writer's guide, the Starfleet calendar system was invented to deemphasize the in-universe date. As the guide puts it, "We invented 'Stardate' to avoid continually mentioning Star Trek's century (actually, about two hundred years from now), and getting into arguments about whether this or that would have developed by then."

Speaking on the 1988 documentary  "Inside Star Trek: The Real Story," de Forest emphasized that this almost wasn't the case since the original script contained dates from the Gregorian calendar. Upon reviewing the script, de Forest felt this didn't feel right for the future spacefaring society. As a solution, he pitched the Julian-inspired concept, which the tech advisor felt had a futuristic vibe thanks to its use of decimals.

While  "Star Trek" creator Gene Roddenberry  liked the concept as a jumping-off point, his version was always meant to be a little esoteric, as Samuel A. Peeples, who wrote the second pilot for "Star Trek: The Original Series," recounted in  "Gene Roddenberry: The Myth and Man Behind Star Trek."  According to Peeples, "We tried to set up a system that would be unidentifiable unless you knew how we did it." Conceptualizing the revised stardate system over drinks, Roddenberry and Peeples took into account the weirdness of space and relative time, ultimately concluding that any  date-related continuity errors in "Star Trek"  could be chalked up to these issues. Or as the "Star Trek" writer's guide put it, "Stardates are a mathematical formula which varies depending on location in the galaxy, velocity of travel, and other factors, can vary widely from episode to episode." In other words, don't think too hard about it.

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Star Trek : Stardate Calculator

Tool will convert standard dates to stardates and vice versa.

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Star Trek: Here's How Stardates Work

Though its development was surprisingly tough, Star Trek's Stardate has a built-in determination system. Here's how it works.

Star Trek ’s Stardate is an integral part of the franchise. At this point, it has become so elaborate that fans can accurately track the course of events throughout the Trek universe simply by checking the Stardate. Like so much about the first series, it didn’t start out that way. It was created solely to disguise the precise date of the show’s future, and it was only through Trek's  phenomenal success that it grew into something larger. A tangled development process led to confusion about how the system works. In actuality, the basics are quite simple.

The Original Series cemented the concept’s status by repetition. William Shatner’s “Captain’s Log” voice-overs were a strong way to provide plot exposition, and the Stardate sounded like something a space captain would use in the future. It started every episode of the first series, then continued with Patrick Stewart on Star Trek: The Next Generation   and subsequent series. During the build-up to  Star Trek: Discovery 's premiere, Star Trek’s Twitter  began counting off Stardates leading to the in-universe date of the first episode.

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Canonically, Stardates are intended to provide a universal calendar for governments spanning numerous planets and cultures, as well as the normality of spaceships that could surpass the speed of light and thus violate notions of relativity. In The Making of Star Trek book, Roddenberry reveals that he invented it to get around awkward questions of when certain technologies were invented. He planned for the Stardates to advance every episode but didn’t get more specific than that.

That changed when reruns of The Original Series began to air out of order, and sharp-eyed fans noticed the Stardates jumping back and forth every week. Roddenberry struggled to set a measurable timetable to explain the notion, which carried over into the development of The Next Generation , where he was determined to set the record straight. A five-digit code was developed and refined, with a few easy hints to let the writers and fans keep track of it. Star Trek has stuck with it ever since.

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The “rebooted” Stardate and the best spot to explain how it works occurred with The Next Generation series premiere, “Encounter at Farpoint.” The episode began on Stardate 41153.7, which matches the year 2364 on the real-world calendar when the episode supposedly takes place. The digit “4” represents the 24 th century, and the first “1” represents the first season of The Next Generation. The remaining numbers advance throughout the season until season 2 when the “41xxx.x” jumps to “42xxx.x.”

That means 1000 units in Stardate measurement are equivalent to a calendar year on Earth. Subsequent seasons of The Next Generation stuck with that yardstick, as did Star Trek: Deep Space Nine and all series thereafter. It’s not without problems. For example, by following its formula, Stardates were established in the year 2323, well after The Original Series and the first six movies that all used the Stardate system. But it’s been internally consistent, and Michael Burnham’s log entry in Discovery, Season 3, Episode 3, “People of Earth,” mentions the Stardate as 865211.3, which matches the show’s 32nd-century setting.

The inconsistencies may have been part of the reason why Discovery launched forward in time. The Stardates, like a lot of other canon content, were looming uncomfortably close, and the move 900 years into the future let the show find its own rhythm. But it’s a testament to how embedded the Stardate notion has become to Star Trek as a whole  and how it remains useful to the series even with its uneven application.

KEEP READING:  Woman in Motion Director Explores Star Trek's Nichelle Nichols' NASA Legacy

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How to Calculate Stardates

Last Updated: September 23, 2023

wikiHow is a “wiki,” similar to Wikipedia, which means that many of our articles are co-written by multiple authors. To create this article, volunteer authors worked to edit and improve it over time. This article has been viewed 62,532 times. Learn more...

Stardate is the dating system used in Star Trek. In the original series, they just made it up; so long as the next stardate was after the current stardate, it worked. Later on, it got a bit more serious.

Converting from Common Date to Stardate

Converting from Stardate to Common Date

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Stardates in Star Trek FAQ

Frequently Asked Questions about Stardates in Star Trek.

This FAQ about Stardates in Star Trek was compiled and written by Andrew Main [email protected] with numerous contributions by others.

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Star Trek Stardate Calculator

About these tools.

These web-based tools can convert between calendar dates and Star Trek Stardates, and are useful for fan fiction writers or role-playing game (RPG) participants.

The calculations are based on prior work by Phillip L. Sublett of TrekGuide.com.

Calendar date to TNG Stardate

Tng stardate to calendar date, calendar date to tos stardate.

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TOS Stardate to Calendar date

Star Trek Stardate

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First Star Trek Stardate Calendar , 1997

Star Trek Stardate is a series of Star Trek desk calendars that began production in 1996 for the year 1997 . They have one page for each day of the year, and feature pictures and quotations from all Star Trek productions.

The calendars are co-publications of Pocket Books and Andrews McMeel Publishing .

Calendars produced [ ]

• Star Trek Stardate Calendar (1997)
• Star Trek Stardate Calendar (1998)
• Star Trek Stardate Calendar (1999)
• Star Trek Stardate Calendar (2000)
• Star Trek Stardate Calendar (2001)
• Star Trek Stardate Calendar (2002)
• Star Trek Stardate Calendar (2003)
• Star Trek Stardate Calendar (2004)
• Star Trek Stardate Calendar (2005)
• Star Trek Stardate Calendar (2006)
• Star Trek Stardate Calendar (2007)

Memory Beta, non-canon Star Trek Wiki

A friendly reminder regarding spoilers ! At present the expanded Trek universe is in a period of major upheaval with the continuations of Discovery and Prodigy , the advent of new eras in gaming with the Star Trek Adventures RPG , Star Trek: Infinite and Star Trek Online , as well as other post-57th Anniversary publications such as the ongoing IDW Star Trek comic and spin-off Star Trek: Defiant . Therefore, please be courteous to other users who may not be aware of current developments by using the {{ spoiler }}, {{ spoilers }} OR {{ majorspoiler }} tags when adding new information from sources less than six months old (even if it is minor info). Also, please do not include details in the summary bar when editing pages and do not anticipate making additions relating to sources not yet in release. THANK YOU

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A rendering of a Federation stardate.

The stardate is a comprehensive calendar system and unit of time measurement in the United Federation of Planets . The system of measuring time was introduced as a singular way for the many different civilizations of the Federation to have a unified time system.

The Federation were not the first to develop a stardate system. In the 2150s , the Xindi used them as a way of recording time. The system was also considered by the Vulcans at the same time. ( ENT episode : " Damage ")

In either 2175 or 2176 , stardates began being used for the first time, though Terran dates remained more popular. ( TOS novel : Strangers from the Sky ; NF - Double Helix novel : Double or Nothing )

There are multiple systems of rendering stardates for easy understanding, leading to there being different expressions of stardates that could possibly refer to the same date. For example, the reference stardate system includes a prefix to show the progression of centuries, while shipboard stardates omit such prefix arrangements and are rendered differently. ( FASA RPG module : Cadet's Orientation Sourcebook , et al. FASA RPG modules and supplements )

During the USS Enterprise (NCC-1701) 's first five-year mission between 2246 and 2251 , the Federation were still preferring to use Terran dates as the standard time-keeping preset, but Captain Robert April decided that a better system needed to be used and outlined to Starfleet Command , upon the Enterprise 's return to Earth in 2251 , how the stardate system was more precise as a spacefaring method of timekeeping. ( TOS - Enterprise Logs short story : " Though Hell Should Bar the Way ")

In the 24th century , Starfleet 's Department of Temporal Investigations has agents trained to know a stardate down to the exact day and hour of an event. ( DS9 episode & novelization : Trials and Tribble-ations )

Stardate expressions [ ]

External link [ ].

• Stardate article at Memory Alpha , the wiki for canon Star Trek .
• 1 ISS Enterprise (NCC-1701)
• 3 Ferengi Rules of Acquisition

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A Trekkie’s Guide To Navigating the Star Trek Timeline

With a narrative that spans seven decades and more than three times as many shows and movies, determining how to watch Star Trek might seem like a daunting prospect. Whether you’re new to the franchise or want to know how to watch the series following the in-universe chronology, this guide should help.

What is a stardate?

To avoid placing Star Trek in a specific century, the franchise has its own system of time: the stardate system. Originally inspired by the Modified Julian date system used by astronomers, writers, and producers have selected numbers using different methods over the years (some more arbitrary than others), which makes it impossible to convert all of the stardates to equivalent calendar dates.

What to know about the Star Trek timeline?

How time works in Star Trek, and how it’s impacted by Starfleet’s time travel shenanigans, is debated amongst the most devoted followers of the Church of Trek. But for casual fans, the first thing it’s necessary to know is that the Star Trek Universe consists of two timelines: the prime timeline and the Kelvin timeline. Although two timelines exist, most of the franchise’s films, shows, and tie-ins take place on the prime timeline.

The second thing to know is that Star Trek’s timelines are always subject to change. Due to the nature of time travel in the franchise, entries appearing earlier on the prime timeline can be impacted and changed (very important to remember) by events that happen later on. For example, the Star Trek: Enterprise season 2 episode “Regeneration” follows up on the events of Star Trek: First Contact .

How to watch the Star Trek prime timeline in chronological order

Here’s how to watch Star Trek ‘s prime timeline in chronological order:

Star Trek: Enterprise (stardates: 2151 – 2155)

Star Trek: The Original Series pilot “The Cage” (stardate: 2254)

Star Trek: Discovery seasons 1 and 2 (stardates: 2256 – 2258)

Star Trek: Strange New Worlds (stardates: 2259 – 2260)

Star Trek: The Original Series (stardates: 2265 – 2269)

Star Trek: The Animated Series (stardates: 2269 – 2270)

Star Trek: The Motion Picture (stardate: 2272)

Star Trek II: The Wrath of Khan (stardate: 2285)

Star Trek III: The Search for Spock (stardate: 2285)

Star Trek IV: The Voyage Home (stardate: 2286)

Star Trek V: The Final Frontier (stardate: 2287)

Star Trek VI: The Undiscovered Country (stardate: 2293)

Star Trek: The Next Generation (stardates: 2364 – 2370)

Star Trek: Deep Space Nine (stardates: 2369 –2375)

Star Trek Generations (stardate: 2371 and some in 2293)

Star Trek: First Contact (stardate: 2373)

Star Trek: Insurrection (stardate: 2375)

Star Trek: Voyager (stardates: 2371 –2378)

Star Trek: Nemesis (stardate: 2379)

Star Trek: Lower Decks (stardates: 2380 – 2381)

Star Trek: Prodigy (stardates: 2383 – 2384)

Star Trek: Picard (stardates: 2399 – 2402)

Star Trek: Discovery seasons 3 and 4 (stardates: 3188 – 3190)

What about the J.J. Abrams’ Star Trek movie trilogy? 

As touched on above, there are two timelines in Star Trek . The J.J. Abrams movies take place on the Kelvin timeline, a parallel timeline created when a 24th-century Romulan, Nero, travels back in time to 2233 (between Ent and Disco season 1, for those keeping track) and splits the timelines in two. 

Most of the Kelvin timeline takes place around the TOS ‘s timeframe but on an alternate timeline. Well, at least so far. 

Here’s how to watch all three movies in the Kelvin timeline in chronological order:

Star Trek (2233)

Star Trek Into Darkness (2259 – 2260)

Star Trek Beyond (2263)

(featured image: Paramount Pictures)