Star Trek's stardates explained: How they're calculated & what they mean

Star Trek famously treats space as the final frontier, but the franchise hasn't forgotten about how it navigates time, either. I'm not talking about the countless time-travel episodes here, but rather the infamously complex stardate system that's existed in several forms since The Original Series. While stardates aren't necessary to understand what's going on, Star Trek has long made use of the fictitious system put in place to keep track of events. However, the beloved sci-fi saga has been far from consistent with how stardates work.

That being said, some eras have applied a relatively solid logic to calculating stardates. Some shows don't use stardates at all. While largely a worldbuilding effort more than anything else, stardates have quietly become one of the cornerstones of Star Trek lore. There will be certain fans who will claim to understand exactly how stardates work, and it's important that you don't believe them. I doubt even the writers knew exactly how it all functioned, if there was ever an ironclad way of figuring it out. Still, it's a fun thing to discuss.

Why Stardates Exist in Star Trek

In the real world, we generally navigate time using the Gregorian calendar. There are a few countries that use alternative calendars, but the Gregorian is essentially the international standard. This is not the first calendar humanity has ever used. As such, Star Trek uses that fact to assume that the use of the Gregorian calendar may also one day meet the end of its usefulness, and that something more specific may come along. The Original Series softly confirmed this was the case in the 23rd century with the introduction of stardates. With more than one planet to account for – after all, alien societies obviously don't use the Gregorian calendar – a new, more universal system of navigating time was developed.

So, Stardates mean humanity wouldn't organize a meeting with the Vulcans on March 16 and be met with even more vacant expressions than usual. A stardate would be established instead. That being said, humans did continue to use the Gregorian calendar for more personal or Earth-centric matters in Star Trek canon. For example, various Star Trek series still have characters discussing recognizable year formats and the traditional dating system. Captain Picard's birthday has been confirmed as July 13 – that kind of thing.

In other words, stardates never fully replaced the Gregorian calendar, but offered a solution to organizing things involving multiple alien societies. Furthermore, because Star Trek: Enterprise's 22nd-century setting omits stardates in favor of the traditional Gregorian format, it's assumed that stardates were a product of the Federation, not Starfleet. The United Federation of Planets only forms right at the end of Enterprise, but Starfleet (an entirely human organization during this era) is central to the plot throughout. Similarly, Star Trek: Voyager's stardates never stray from the vague format championed by other shows of its era, despite being stranded in the Delta Quadrant. This suggests stardates are tied to a central Federation calculation, rather than being gleaned by scanning nearby stars.

Star Trek Has Never Fully Standardized the Stardate Format

Although Star Trek: The Original Series introduced stardates, there wasn't a whole lot of thought that went into them. They were instead written as technical-sounding sci-fi patter that wasn't intended to be parsed by the audience. Viewers did try to figure out what the stardates meant, though, and they immediately found them to be nonsense. Stardates have since been established as going in ascending order as time goes by, but The Original Series didn't have this rule yet. As a result, lower stardates would often be established in episodes that followed an installment with a higher stardate, and vice versa. There was no sense of linear progression in the calculations.

This would thankfully go on to be somewhat fixed in the TOS-era movies, making it feel like there was more of a concrete system in place. However, while the stardates did ascend during the movies, there was no obvious connection between the figures being read out by Kirk (William Shatner) and company, and the date back on Earth. That particular wrinkle wouldn't happen until The Next Generation. Captain Picard (Patrick Stewart) and his crew were the first to benefit from a somewhat logical stardate format. It has remained the primary method of calculating stardates in relation to the Gregorian calendar – at least for the '90s shows. It still isn't airtight, though. For some (seemingly arbitrary) reason, fans have figured out that TNG's rules mean stardate 0 is the Earth year 2323. Anything before that year doesn't really fit the code.

TNG's first episode, "Encounter at Farpoint," is used as the true genesis point of this rough stardate calculation. The installment takes place on stardate 41153.7. Let's ignore the .7 for now, and say it's just 41153. Using the reverse-engineered formula established by Trekkies over the years, it's possible to figure out a rough equivalent in terms of when TNG's pilot takes place on the Gregorian calendar. It's the stardate (41153), divided by 1000. 41153 divided by 1000 equals 41.153. Again, let's streamline it to 41. Those 41 years can be added to Star Trek's stardate 0, which has been figured out to be 2323.

That would amount to the year 2364, which is exactly when "Encounter at Farpoint" is set. The stardate progression from there is that roughly 1000 stardate units = a single Earth year. (That's why we divided by 1000 earlier.) For instance, stardate 42153 would be somewhere in the region of 2324. While somewhat helpful, this doesn't tell us the month or date, only the year. The other digits do suggest this other information, but there's no real way of knowing what's accurate. What these TNG-era stardates do reveal is how far through a particular day we are. Remember that .7 from earlier? That means the "day" is .7 of the way to completion. Just .3 more of a "day," and it'll be time to change that stardate from 41154 to 41155. This same formula can be applied to Deep Space Nine and Voyager, but remember, it's not a perfect (or even official) system.

Modern Star Trek Projects Have Overhauled Stardates Yet Again

Just as Star Trek had established something of a pattern for stardates, the franchise backtracked once more. Enterprise reverted to the Gregorian calendar, which made sense given that it was a prequel to everything. Discovery was the first Star Trek series in years when it debuted in 2017, but it largely avoided stardates. Most of its successors have followed suit in this respect. But when stardates are used, they tend not to abide by the loose TNG formula.

JJ Abrams' Kelvin Timeline made things way easier. In those movies, Stardate 2233.04 means it's the year 2233, and that it's the fourth day of the year. Considering the movies were made as a reboot, welcoming in a new generation of Star Trek fans, it made sense to take a more simplistic approach like this. Still, it's important to remember that the Kelvin Timeline trilogy unfolds in an alternate reality. So, the streamlining of stardates to something so Earth-centric arguably makes very little sense given Star Trek's original reason for developing stardates.