How to Calculate Stardates. According to Star Trek creator Gene Roddenberry, stardates are not only based on the calendar date, but are a representation of a starship's location in the galaxy, it's speed and direction of travel. There's no real system you can use to calculate a stardate; however, this hasn't stopped people from trying to make sense of the stardates given in the television episodes.
Format the current date and time so it looks like a stardate. Begin with a digit for the century (1 for the 21st century), followed by a digit for the year and then digits for the month and day. For example, the date January 15, 2001 would be 1101.15.
Search the Internet for stardate calculators based on the conventions established in either the original Star Trek series or those of subsequent series. If you don't want to use a calculator, assume that midnight on May 25, 2322 was stardate 0000.00 and work backward. Using this convention, the numbers after the decimal represent the hour of the day.
Use stardates based on the convention established in Star Trek: The Next Generation. These dates begin with the number 4 to represent the 24th century. The next digit represented the television season the show aired in. After 10 years, the numbers "rolled over" to begin stardates (in subsequent series) with the number 5. According to this convention, imagine that Star Trek: The Next Generation is still on the air and beginning with 4 plus the season number, add the month and date. The first season of Star Trek: The Next Generation began in 1987.
Make up your own system. Begin with a date you want to use as year zero, divide up the year and day into the number of parts that make sense to you and do you own calculations. Remember that a year is one revolution around the sun and a day is one rotation, no matter what system you devise.
No matter how you decide to calculate stardates, some other Star Trek fan is going to say you're doing it wrong. If you don't want to argue about it, keep your system to yourself.