What is your age on other planets?
A year is the time a planet takes to go once around the Sun. Earth takes 365.25 days. Mars takes 687. Jupiter takes almost 12 Earth years. Your age is how many of those laps you've been alive for, so it depends on which planet is counting.
On Mercury, a 30-year-old has had 125 birthdays. On Neptune, the same person is 0.18. Nobody alive today has finished one Neptune year. The Age on Other Planets tool takes your date of birth, counts the Earth days you've been alive, and divides by each planet's year length. You get your age on all eight planets plus Pluto, using orbital periods from NASA's planetary fact sheets.
No signup, nothing to install. Type a date, get nine numbers.
How to find your age on other planets
- Pick your date of birth in the date field. Dates after today aren't accepted.
- Read the green card at the top. It's your age in Earth years, with the number of days you've been alive in brackets.
- Scan the planet cards. Each one shows your age in that planet's years, and how long one year there lasts in Earth days.
That's it. You don't need to know your age in days; the tool works it out. Try a child's birthday to see that a 10-year-old is 5.32 on Mars, or a grandparent's to see how close they are to 3 on Saturn.
The formula: planet age from Earth days
The math is one division per planet.
Age on a planet = days you've been alive ÷ length of that planet's year in Earth days
Worked example, for someone exactly 30 Earth years old. That's 30 × 365.25 = 10,957.5 days. Divide by each planet's year:
| Planet | One year, in Earth days | Math | Age the tool shows |
|---|---|---|---|
| Mercury | 87.969 | 10,957.5 ÷ 87.969 | 125 |
| Venus | 224.701 | 10,957.5 ÷ 224.701 | 48.8 |
| Earth | 365.25 | 10,957.5 ÷ 365.25 | 30.0 |
| Mars | 686.971 | 10,957.5 ÷ 686.971 | 16.0 |
| Jupiter | 4,332.589 | 10,957.5 ÷ 4,332.589 | 2.53 |
| Saturn | 10,759.22 | 10,957.5 ÷ 10,759.22 | 1.02 |
| Uranus | 30,685.4 | 10,957.5 ÷ 30,685.4 | 0.36 |
| Neptune | 60,189 | 10,957.5 ÷ 60,189 | 0.18 |
| Pluto (dwarf) | 90,560 | 10,957.5 ÷ 90,560 | 0.12 |
The tool rounds the way the table does: whole numbers from 100 up, one decimal from 10 to 99, two decimals below 10. Mercury's unrounded answer is 124.56; Mars's is 15.95.
No calculator handy? Divide your Earth age by these: Mercury 0.24, Venus 0.62, Mars 1.88, Jupiter 11.86, Saturn 29.46, Uranus 84.01, Neptune 164.79, Pluto 247.94. A 20-year-old on Mars: 20 ÷ 1.88 = 10.6.
Your age on every planet, at common ages
Skip the math. Here's what familiar Earth ages look like across the Solar System, rounded the way the tool rounds them.
| Earth age | Mercury | Venus | Mars | Jupiter | Saturn | Uranus | Neptune |
|---|---|---|---|---|---|---|---|
| 5 | 20.8 | 8.13 | 2.66 | 0.42 | 0.17 | 0.06 | 0.03 |
| 10 | 41.5 | 16.3 | 5.32 | 0.84 | 0.34 | 0.12 | 0.06 |
| 13 | 54.0 | 21.1 | 6.91 | 1.10 | 0.44 | 0.15 | 0.08 |
| 18 | 74.7 | 29.3 | 9.57 | 1.52 | 0.61 | 0.21 | 0.11 |
| 21 | 87.2 | 34.1 | 11.2 | 1.77 | 0.71 | 0.25 | 0.13 |
| 30 | 125 | 48.8 | 16.0 | 2.53 | 1.02 | 0.36 | 0.18 |
| 40 | 166 | 65.0 | 21.3 | 3.37 | 1.36 | 0.48 | 0.24 |
| 50 | 208 | 81.3 | 26.6 | 4.22 | 1.70 | 0.60 | 0.30 |
| 65 | 270 | 106 | 34.6 | 5.48 | 2.21 | 0.77 | 0.39 |
| 80 | 332 | 130 | 42.5 | 6.74 | 2.72 | 0.95 | 0.49 |
A few things jump out. You turn 100 on Mercury at about 24 Earth years old, and on Venus at about 61.5. You'd be 33.85 on Earth before you turned 18 on Mars. An 80-year-old still hasn't had a first birthday on Uranus. That takes 84 Earth years.
Planet years to Earth years
Going the other way? Here's how long one year on each planet lasts in Earth time. It's also the Earth age at which you'd celebrate your first birthday there.
| Planet | 1 planet year in Earth days | 1 planet year in Earth years | Your first birthday there |
|---|---|---|---|
| Mercury | 87.969 | 0.24 | About 3 months old |
| Venus | 224.701 | 0.62 | About 7.4 months old |
| Mars | 686.971 | 1.88 | About 1 year 10½ months old |
| Jupiter | 4,332.589 | 11.86 | Just before your 12th Earth birthday |
| Saturn | 10,759.22 | 29.46 | About 29½ |
| Uranus | 30,685.4 | 84.01 | 84 |
| Neptune | 60,189 | 164.79 | Nearly 165 |
| Pluto | 90,560 | 247.94 | Nearly 248 |
To turn planet years into Earth years, multiply by the third column. Ten Venus years is 10 × 0.62 = 6.2 Earth years (6.15 unrounded). Two Jupiter years is 23.7 Earth years. The tool only goes from your birthday to planet ages, so use this table for the reverse.
Neptune was discovered in 1846. It finished its first full orbit since then in 2011. In all the time we've known Neptune exists, it has gone around the Sun once.
How old are the planets themselves?
Some people searching "age of Jupiter" or "how old is Mars" mean the planet's own age, not theirs. Short answer: all the planets are about 4.5 billion years old. They formed from the same disk of gas and dust around the young Sun, about 4.6 billion years ago. Earth is about 4.54 billion years old. Jupiter probably formed first, within the first few million years. Its age in its own years doesn't mean much. Its age in time is the same as everyone else's in the Solar System, give or take a few million years.
Edge cases and what the numbers don't tell you
Pluto is included, and labeled
The International Astronomical Union made Pluto a dwarf planet in 2006. The tool keeps it, because people still ask for their Pluto age, and marks it with a "dwarf" tag. One Pluto year is 248 Earth years, so no one has ever lived through one.
Why Earth uses 365.25 days
The other planets use their sidereal year, one full lap measured against the distant stars. Earth's sidereal year is 365.256 days. The tool uses 365.25 for Earth instead, the average calendar year with leap days. The difference is about 1.5 hours per decade, and it keeps your Earth age matching your birthday.
Years, not days
This tool counts years. A day is a separate thing: one spin of the planet. They can be strange. A full sunrise-to-sunrise day on Mercury lasts about 176 Earth days, two of its years. Venus takes 243 Earth days to spin once, longer than its 225-day year. A Mars day is close to ours, about 24 hours 40 minutes. The tool doesn't convert day lengths.
It counts to the moment
Your age in days is measured from midnight on your birth date to right now, in your time zone. So the numbers creep up while the page is open. The Earth card is rounded, so in the day or so before your birthday it may already show your new age.
Related time and date tools
For your exact Earth age in years, months and days, use the Age Calculator. The Age in Days Calculator gives the day count this tool divides. Curious what you'd weigh out there? Weight on Other Planets does the same tour for gravity. Cosmic Address zooms out from Earth to the edge of the observable universe. And Life in Weeks puts your whole life on one grid, Earth weeks only.
Frequently asked questions
How old am I on Mars?
Divide your Earth age by 1.88. A Mars year is 686.971 Earth days. A 30-year-old is 15.95 on Mars, which the tool shows as 16.0. A 10-year-old is 5.32.
How old am I on Jupiter?
Divide your Earth age by 11.86. A 30-year-old is 2.53 on Jupiter. You turn 1 on Jupiter just before your 12th Earth birthday, and 6 at about 71.
How old would I be on Mercury?
Multiply your Earth age by about 4.15. A Mercury year is only 88 Earth days. A 20-year-old is 83 on Mercury, and you pass 100 there at about 24.
How do I convert Venus years to Earth years?
Multiply by 0.615. One Venus year is 224.701 Earth days, or 0.62 Earth years. So 10 Venus years is about 6.15 Earth years.
Which planet would make me the oldest?
Mercury, because its year is the shortest. Neptune makes you youngest of the eight planets, and Pluto younger still.
Does this account for leap years?
Yes. The tool counts the real days between your birth date and today, leap days included. The 365.25 figure for Earth is the long-run average of three 365-day years and one 366-day year.
Can I see my age on the Moon?
Not here. The Moon orbits Earth, not the Sun, so it shares Earth's year. Your age in Moon orbits would be a different calculation.