Your age on other planets

A "year" is one trip around the Sun, and every planet takes a different time. Here's how old you'd be on each, and when your next birthday would come round.

Orbital periods

Planet	One year in Earth days	In Earth years
Mercury	87.97	0.24
Venus	224.7	0.62
Earth	365.256	1.00
Mars	686.98	1.88
Jupiter	4,332.59	11.86
Saturn	10,759.22	29.46
Uranus	30,688.5	84.02
Neptune	60,182	164.77

Sidereal orbital periods from NASA's planetary fact sheets.

Why inner planets make you older

Planets closer to the Sun travel a shorter path and move faster (Kepler's third law: the square of the orbital period grows with the cube of the distance). Mercury zips round in 88 days, so a 30-year-old has had about 124 Mercury birthdays. Neptune takes almost 165 Earth years; nobody alive has seen a single Neptune birthday.

A "day" differs too: on Venus one solar day lasts about 117 Earth days, so a Venus year is less than two Venus days long.

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Questions people ask

How do you calculate your age on another planet?

Divide the number of days you have been alive by the length of that planet's year in Earth days. Mars takes 687 Earth days to orbit the Sun, so someone who has lived 10,000 days is about 14.6 Mars years old.

How old would I be on Mars?

Roughly your Earth age divided by 1.88. A 30-year-old is about 16 on Mars.

On which planet would I be the oldest?

Mercury, which orbits the Sun every 88 days. Your Mercury age is about 4.15 times your Earth age.