Choose an epoch
Use 1957 for the beginning of the Space Age or 2323 for a future-facing fictional reference.
Temporal conversion utility
Earth date in. Stardate out.
Convert any date using two distinct epochs, or edit a stardate to travel back to its matching Earth date.
Conversion parameters
Calculated stardate
SD
Tip: edit the number to reverse-convert
Methodology
A consistent system for an imaginary clock.
Stardates are fictional, so this tool uses a transparent mathematical model: 1,000 units per Earth year, with the day determining the fractional remainder.
Count complete years
Each full year after—or before—the selected epoch contributes 1,000 stardate units.
Add the day fraction
The day of the year is converted proportionally, with leap years handled automatically.
SD = 1000 × (year − epoch) + day fraction
Questions
Stardate basics
How is a stardate calculated?
Each Earth year equals 1,000 stardate units. The date’s position within the year supplies the remaining fraction, adjusted for leap years.
Are stardates real?
No. Stardates are fictional. This calculator offers a consistent interpretation for entertainment, writing, and experimentation.
Why are there two epochs?
The 1957 option anchors the scale to Sputnik and the beginning of the Space Age. The 2323 option provides a fictional future epoch inspired by science-fiction timelines.
Keep it online
Support the developer
Stardate.info is free to use. If it made your day a little more fun, you can help support ongoing hosting and improvements.