Decimal Time

Stardates are used in most of the fictional Star Trek TV series, movies and books. They are represented with a whole part of four or five digits, and a fractional part, usually a single decimal digit. These can be divided into two eras: the 23rd century, including the original series (TOS), the animated series and the first six movies, which used four digits (1234.5); the 24th century, including the The Next Generation, Deep Space 9, Voyager and the later movies, which used five digits (12345.6). (Enterprise was set in the 22nd century and did not use stardates.) This can be shown as follows:

Series	Stardate	Year1	Released
22rd Century
Star Trek: Enterprise	None	2151	9/2001
	None	2155	5/2005
23rd Century
Star Trek (The Original Series)	1312.4	2265	9/1966
	5943.9	2269	3/1969
Star Trek: The Animated Series	1254.4	2269	10/1973
	6770.3	2270	10/1974
Movies 1 2 3 4 5 6	7412.6	2272	9/1979
	9521.6	2293	12/1991
24th Century
Star Trek: The Next Generation	41153.7	2364	9/1987
	47988.0	2370	5/1994
Movies 7 8 9 10	48650.1	2371	11/1994
	56844.9	2379	12/2002
Star Trek: Deep Space Nine	46379.1	2369	1/1993
	52861.3	2375	5/1999
Star Trek: Voyager	48315.6	2371	1/1995
	54973.4	2378	5/2001
1 From Star Trek Chronology

In the 24th century, the stardates generally progress by a fairly constant 1000 units per year, both in relation to 24th century dates given in episodes and to when episodes were actually released in the 20th and 21st centuries. Thus, there are about 15 years between the 41000's and the 56000's. Working backwards, this gives an initial epoch of 2323, which is decades after when the original series and associated movies are set, suggesting that a different system was being used in the late 23rd century.

In addition, various references suggest that one stardate equals one day, and that the digits to the right of the decimal represent tenths of a day. However, this contradicts the accepted rate of 1000 stardates in an earth year of 365 days. But if there was always a one-to-one ratio of stardates to earth days, then one hundred years would be 36524 stardates. Coincidently, the first episode of The Next Generation was on stardate 41153, and subtracting 36,524 gives 4629, which was in the range of the original series, set just about one century earlier.