Age on Other Planets

Your age on a planet is the number of days you have been alive divided by that planet's orbital period (its year) in Earth days. For example, someone who has lived 9,000 days is 9,000 ÷ 686.98 ≈ 13.1 years old on Mars.

In Earth days: Mercury 88, Venus 224.7, Earth 365.26, Mars 687, Jupiter about 4,333 (11.86 Earth years), Saturn about 10,759 (29.46 years), Uranus about 30,685 (84 years) and Neptune about 60,189 (164.8 years). Pluto takes about 248 Earth years.

Divide your age in Earth years by about 1.88. A 30-year-old is roughly 16 Mars years old. The calculator uses exact days, so it also tells you the date of your next Mars birthday.

Neptune takes almost 165 Earth years to go around the Sun once, so nobody alive today has completed a full Neptune year. Your age there is a fraction such as 0.2.

No. A year is one orbit around the Sun, while a day is one spin on its axis. Venus is unusual: one rotation takes about 243 Earth days, longer than its 225-day year.

It uses sidereal orbital periods, the time to orbit the Sun once relative to the stars, as published by NASA: Mercury 87.969, Venus 224.701, Earth 365.256, Mars 686.980, Jupiter 4,332.59, Saturn 10,759.22, Uranus 30,685.4, Neptune 60,189 and Pluto 90,560 Earth days.