How is my age on another planet worked out?

Your age in Earth years is divided by the number of Earth years that planet takes to orbit the Sun once. A year on Mars lasts 1.88 Earth years, so your Mars age is your Earth age divided by 1.88, which is why you are always younger on the outer planets.

Why am I younger on Jupiter than on Earth?

A planet's year is one full trip around the Sun, and the further out a planet is, the longer that trip takes. Jupiter takes almost 12 Earth years for a single orbit, so you have completed far fewer Jupiter years than Earth years, making your Jupiter age much smaller.

Which planet makes me oldest?

Mercury, the closest planet to the Sun, has the shortest year at just 88 Earth days, so you rack up Mercury years more than four times as fast as Earth years. That makes your Mercury age the largest of any planet in the solar system.

Age on Other Planets Calculator

This calculator shows how old you would be on every planet in the solar system, from Mercury out to Neptune, based on your Earth date of birth. The idea is simple and rather lovely: a year is one trip around the Sun, and every planet takes a different amount of time to make that trip, so your age changes completely depending on where you count it. Mercury races round the Sun in just 88 days, so a Mercury year flies by and your Mercury age is the largest of all. The outer planets crawl by comparison, with Neptune taking almost 165 Earth years for a single lap, so on Neptune even a long human life is well under one year old. You enter your date of birth and the calculator counts the actual days you have lived, converts that to Earth years, then divides by each planet's orbital period to give your age in that planet's own years. It is a favourite for classrooms, science fairs and curious kids, a fun way to bring the scale of the solar system to life and to see just how differently time would pass on each world. The ages update the moment you change the date, so try your own, a friend's, or a famous birthday.

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Date of birth

31.13

your age in Earth years

On Mercury129.26

On Mars16.55

On Jupiter2.62

Each age is your Earth age divided by that planet's orbital period. Ages are in that planet's own years and are rounded to two decimal places.

Planet	Year length (Earth years)	Your age
Mercury	0.24	129.26
Venus	0.62	50.61
Earth	1.00	31.13
Mars	1.88	16.55
Jupiter	11.86	2.62
Saturn	29.45	1.06
Uranus	84.02	0.37
Neptune	164.79	0.19

Year lengths are each planet's sidereal orbital period, the time for one full orbit of the Sun. Pluto is not included as it is classed as a dwarf planet. A bit of fun rather than an official measure of age.

How it works

The calculator first counts the whole days between your date of birth and today, then divides by 365.25 to get your age in Earth years, the 0.25 accounting for the leap day every four years. To find your age on another planet, it divides your Earth age by how many Earth years that planet takes to orbit the Sun once. Mercury's orbit takes only 0.24 Earth years, so dividing by a number smaller than one makes your Mercury age larger. Neptune's orbit takes 164.79 Earth years, so dividing by that large number makes your Neptune age tiny. The same single figure, your Earth age, drives every planet: only the divisor changes.

Worked example

Take someone born on 15 June 1995. As at 2 August 2026 they have lived 11,371 days, which is 31.13 Earth years. Dividing by Mercury's orbital period of 0.24 gives a Mercury age of 129.26, while dividing by Mars's 1.88 gives 16.55, and dividing by Jupiter's 11.86 gives just 2.62. On distant Neptune, the same person is only 0.19 Neptune years old, not even one full orbit into their life.

Related calculators

Age Calculator: your exact age in years, months and days.
Age in Days Calculator: your age counted in days, weeks and hours.
Age in Seconds Calculator: your age in seconds, minutes and hours.
Birthday Calculator: the day you were born and your next birthday.
Date Calculator: add or subtract days between dates.

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