Stardates are the units of time which are used in Starfleet and the Federation. These units standardise time measurement between various cultures, worlds and races. Stardates are calculated through a complicated equation that takes into account relativistic effects, universal expansion and the effects of gravity on time and space. Every so often the stardate system has to be updated to take into account the expansion of space or other natural effects. Currently there are approximately 200 stardate units to a year. Halfway into the 24th Century the system is expected to need adjusting once more, to keep in touch with the expansion of the Federation and the universe in which it exists.

Author's notes:

Stardates are a tricky things. Until the advent of Star Trek: The Next Generation, no hard and fast rules existed for stardates. One thing is for sure, there were re-calculations between the times of Kirk and Picard. Below is a table of stardates as mentioned in dialogue unless otherwise stated.

Movie/Episode/[Incident] Earth Year Stardate
Star Trek II 2285 8130
Star Trek III 2285 8210
Star Trek IV 2286 8390
Star Trek V 2287 8454
Star Trek VI 2293 9521
Star Trek: Generations 2293 9715
Dark Page [Troi's marriage] 2328 30620*
Sins of the Father [Khitomer Massacre] 2346 23859**
The Pegasus [Pegasus Inquiry] 2359 36764
Encounter at Farpoint 2364 41153
* Mike Okuda notes that the stardate was chosen arbitrarily for the episode.
**Stardate taken from an Okudagram for the Captain's log of the U.S.S. Intrepid arriving at Khitomer. This stardate would seem to adhere to the 1 000 units per year system.

Author's Notes [continued]:

From the above table it is not hard to see that the stardate situation for the Interim Years era is one of the biggest headaches, with no definite solution. Stardate 10 000 was chosen for January 1st 2295, moving the stardate to a 5-digit system as soon as possible. It didn't take complicated maths to discover that a 200 stardate units per year system would fit the gap almost perfectly [Assuming Praxis exploded Jan. 2293 and the Enterprise-B was launched in December, there were 195 stardate units in 2293]. Working forwards, this system allows lee-way towards the time of TNG to allow for a transition to a 1 000 units per year system as is used from the TNG-era onwards. [Backward counting would lead to 'difficulties' and inconsistencies]. Further headaches are there in the data that suggests the 1000 unit per year system is used as of 2359, but also as far back as 2346. I have tried to best fit the stardates to Earth year, but it is an imperfect solution to an imperfect situation. Note: the stardate systems change over on July 1st 2342 [stardate 19501], this fits the old and new systems perfectly. Therefore Picard's first logs on the Stargazer were recorded in the 'old' system, whereas Captain Garrett's final logs were recorded in the 'new' system. Below is a table of Earth year and the stardate on January 1st.

Earth Year Stardate
2288 8520*
2289 8720*
2290 8920*
2291 9120*
2292 9320*
2293 9520
2294 9800
2295 10000
2296 10200
2297 10400
2298 10600
2299 10800
2300 11000
2301 11200
2302 11400
2303 11600
2304 11800
2310 13000
2320 15000
2330 17000
2340 19000
2341 19200
2342 19400
2343 20001**
2344 21001
2345 22001
2346 23001
2350 27001**
2360 37001**
2364 41001**

*Backdating to cover the time between ST:V & ST:VI. Note that the events in Star Trek: New Worlds now cover 2290 - Dec 2291, and not 2292 as the game suggests.

**July 1st 2342 sees the introduction of the 1000 unit/year system. This date has been chosen as it matches up perfectly between the two systems. This system is in keeping with established back-stardating in TNG episodes.

Here is a table that shows how to translate stardates to Earth Dates during the time of this stardate system. The formula for conversion is stardate divided by 200 multiplied by 365. Then you just work out what day of the year that is. Table follows with example dates afterwards:

00 January 1st
22 February 9th
43 March 20th
62 April 23rd
100 July 1st
114 July 26th
137 September 5th
199 Dec 31st

Example dates:
11222 February 9th 2301
11243 March 20th 2301
11300 July 1st 2301
11398 December 28th 2301

Finally, when calculating stardate - Earth date conversion:

MARCH 31 90
APRIL 30 120
MAY 31 151
JUNE 30 181
JULY 31 212
AUGUST 31 243
OCTOBER 31 304

As for leap years, they probably figure in there someplace...

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