About the Age on Other Planets Calculator
Every planet in the solar system takes a different amount of time to complete one orbit around the Sun, and that orbital period is exactly what defines a "year" on that planet. This calculator converts the number of Earth days you've been alive into the equivalent number of years on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, or Neptune.
The formula
The calculation has two steps. First, find the number of Earth days between your birth date and the date you want to check. Then divide that day count by the target planet's orbital period, expressed in Earth days:
- Age on planet (in that planet's years) = Earth days elapsed ÷ planet's orbital period in Earth days
Earth's own orbital period is about 365.256 days (the sidereal year), so the calculator first turns your birth date and "as of" date into a precise day count, then divides that count by whichever planet's orbital period you select.
Orbital periods used
- Mercury: 87.97 Earth days (0.24 Earth years)
- Venus: 224.70 Earth days (0.62 Earth years)
- Earth: 365.26 Earth days (1.00 Earth years)
- Mars: 686.98 Earth days (1.88 Earth years)
- Jupiter: 4,332.59 Earth days (11.86 Earth years)
- Saturn: 10,759.22 Earth days (29.45 Earth years)
- Uranus: 30,688.5 Earth days (84.02 Earth years)
- Neptune: 60,182 Earth days (164.79 Earth years)
These are each planet's sidereal orbital period — the time to complete one full 360-degree trip around the Sun relative to the distant stars — based on published NASA/JPL planetary fact sheets.
Reading the result
The farther a planet orbits from the Sun, the longer its year and the fewer "years" you will have lived there. Someone who is 36 Earth years old has lived only about 19 Mars years, since a Mars year is nearly twice as long as an Earth year — but over 300 Mercury years, since Mercury circles the Sun in under 88 days. This calculator measures orbital years only; it does not account for each planet's own rotation (day length), which is a separate quantity.