Determining Calendar Dates From Stardates
Note: The following Stardate calculations are meant to express general trends across all episodes of each Star Trek series. These calculations are not meant to be accurate for small time scales, such as hours or minutes within a single episode.
Expressing Contemporary Dates as Stardates
Find the fictional Stardate that corresponds to "today's" date
Twenty-fourth Century Stardates
Calculating calendar dates in The Next Generation,
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.
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.
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)
- 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.)
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.
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.
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).
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).
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.
- 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 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.).
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.
- 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.