Age and time

Age on Other Planets

How old would you be on Mars, Jupiter or Neptune? Enter your birth date to see your age on every planet and when your next birthday there will be.

How your planet age is found

A year is one trip around the Sun, and every planet takes a different time. We count the days you have been alive and divide by the length of each planet's year in Earth days, using NASA's orbital periods. Your next birthday on a planet is the day your age there reaches the next whole number.

For your Earth age to the day, use the Age Calculator, or count down to your next Earth birthday with Days Until My Birthday.

Worked example

Born March 21, 1996 and checked on October 2, 2026: that is 11,152 days. A Mars year is 687 days, so 11,152 divided by 687 is 16.23 Mars years.

How to work out your planet age by hand

Count the days you have been alive. The days alive calculator gives the exact number, or multiply your age in years by 365.25 for a close estimate.
Look up the planet's year in Earth days in the table below. Mars is 687.
Divide your days by the planet's year. 11,152 days divided by 687 is 16.23.
The whole number is your age there. For your next birthday on that planet, multiply the next whole number by the planet's year and add that many days to your birth date.

Why your age is different on other planets

The farther a planet is from the Sun, the bigger its orbit and the slower it travels, so its year is longer. Mercury, closest to the Sun at about 58 million km, goes around in 88 days. Earth, at about 150 million km, takes a year. Neptune, about 4,515 million km out, needs about 165 Earth years.

So on planets closer to the Sun than Earth (Mercury and Venus) you are older, and on planets farther out you are younger. The number of days you have lived is the same everywhere: only the size of a year changes.

Your age on each planet if you are 25

A quick reference for a 25-year-old on Earth. Enter your own birth date above for exact ages and dates.

Planet	Age
Mercury	103.76
Venus	40.63
Mars	13.29
Jupiter	2.1
Saturn	0.84
Uranus	0.29
Neptune	0.15
Pluto	0.1

How long is a year on each planet?

Planet	Earth days	Earth years
Mercury	88	0.24
Venus	224.7	0.62
Mars	687	1.88
Jupiter	4,331	11.86
Saturn	10,747	29.42
Uranus	30,589	83.75
Neptune	60,189	164.79
Pluto (dwarf planet)	90,560	247.94

A day and a year on each planet

A day is one turn from sunrise to sunrise; a year is one trip around the Sun. On most planets a day is short and a year is long, but Mercury and Venus are strange: a single day on Mercury lasts about 176 Earth days, longer than its 88-day year.

Planet	One day	One year
Mercury	176 Earth days	88 days
Venus	117 Earth days	225 days
Earth	24 hours	365 days
Mars	24.7 hours	687 days
Jupiter	9.9 hours	11.9 years
Saturn	10.7 hours	29.4 years
Uranus	17.2 hours	83.7 years
Neptune	16.1 hours	164.8 years
Pluto	6 Earth days	247.9 years

Day and year lengths from the NASA Planetary Fact Sheet. Years above 1,000 days are shown in Earth years.

Planet by planet

Mercury. The fastest year, 88 days. A 25-year-old has had more than 100 Mercury birthdays.
Venus. A year of 225 days, but a day of about 117 Earth days, so a day there is more than half a year.
Mars. A year on Mars lasts 669.6 sols (Mars days), the same as 687 Earth days. Its longest season, northern spring, lasts 194 sols.
Jupiter. The biggest planet spins fastest, with a day of under 10 hours, but its year lasts about 12 Earth years.
Saturn. About 29.4 Earth years per orbit, so most people turn 1 there in their late twenties and 2 in their late fifties.
Uranus. About 84 Earth years per orbit. Reaching 1 Uranus year means living past 83.
Neptune. Neptune takes about 165 Earth years to orbit the Sun. Found in 1846, it completed its first full orbit since its discovery in 2011.
Pluto. A dwarf planet with a year of about 248 Earth years.

Reading your results

Planet ages are shown with two decimals. A Mars age of 15.97 means you are almost 16 in Mars years: the .97 is the share of a Mars year you have finished, not months or days. Your next birthday there is the date that number reaches 16.

The milestones under your results pick out fun round numbers, like turning 1 on Jupiter, 18 on Mars or 100 on Mercury, with the date each one happened or will happen. They make a good excuse for a space-themed party, and a classroom can check them by hand with the method above.

Age on Other Planets questions

How old am I on Mars?

Your Earth age times about 0.53, because a Mars year is 687 Earth days. The Mars birthday people most like to mark is 18: you reach it at about 33.9 on Earth, in your early thirties. Enter your birth date above for the exact day.

How old would I be on Jupiter?

Divide your Earth age by about 11.9. Your first Jupiter birthday comes at about 11 years and 10 months old: someone born March 21, 1996 turned 1 there on January 29, 2008, and turns 3 at about 35 and a half.

How old am I on Venus?

About 1.6 times your Earth age, since a Venus year is 225 Earth days. Your first Venus birthday came when you were only 225 days old, just over 7 months, so even a toddler has had a few there.

How old am I on Pluto?

Well under 1. Pluto takes about 248 Earth years to go around the Sun, so a 50-year-old is about 0.2 and a 100-year-old about 0.4. Pluto is classed as a dwarf planet; we include it for fun and label it that way.

Do you age slower on other planets?

No. Your body ages at the same pace wherever you are; only the length of the year you count in changes. A 30-year-old is about 16 in Mars years but has lived exactly as long. Gravity does make clocks run very slightly differently from planet to planet, but the effect is far too small to notice.

Why do other calculators give slightly different numbers?

Small differences come from rounding the length of each year, or from using your age in years instead of the exact number of days you have been alive. We use NASA's orbital periods and your exact days.

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