Showing an example birth date (15 June 2000). Enter yours to update everything.
Your age on every planet
Plus the date of your next birthday on each world.
Your cosmic milestones
Filled dots are milestones you've already reached.
Your age on real exoplanets
Planets around other stars with very short years.
Age lookup table
Find your Earth age to see it on every planet.
Orbital periods from the NASA Planetary Fact Sheet and the NASA Exoplanet Archive.
Enter your date of birth above and the calculator shows your age on all eight planets, Pluto and Ceres, the exact date of your next birthday on each one, and the cosmic milestones you’ve already passed. Scroll further to see how old you’d be on real planets orbiting other stars.
How the calculator works
A year is one trip around the Sun. Each planet takes a different amount of time to make that trip, called its orbital period. The calculator counts how many days you’ve been alive and divides that number by each planet’s orbital period.
The formula is simple:
Age on a planet = days you’ve been alive ÷ length of that planet’s year in Earth days
Mercury finishes an orbit in just 88 Earth days, so you collect Mercury years four times faster than Earth years. Neptune takes almost 165 Earth years to go around once, which means nobody alive today has reached their first Neptune birthday. Orbital periods come from NASA’s Planetary Fact Sheet.
How long is a year on each planet?
| Planet | One year in Earth days | One year in Earth years |
|---|---|---|
| Mercury | 88 | 0.24 |
| Venus | 225 | 0.62 |
| Earth | 365.25 | 1 |
| Mars | 687 | 1.88 |
| Jupiter | 4,333 | 11.86 |
| Saturn | 10,759 | 29.46 |
| Uranus | 30,685 | 84.01 |
| Neptune | 60,189 | 164.79 |
| Pluto (dwarf planet) | 90,560 | 247.9 |
Why your age is different on every planet
Planets closer to the Sun travel a shorter path and move faster, so their years are short. The inner planets, Mercury and Venus, make you “older” than you are on Earth. The outer planets, from Mars to Neptune, take longer to circle the Sun, so you’re “younger” there. A 30-year-old is about 125 on Mercury, 16 on Mars and only 2.5 on Jupiter.
Your age is almost never a whole number on another planet. You’re partway through your current year there, the same way you’re partway to your next birthday on Earth right now.
Your next birthday on other planets
Because Mercury’s year is so short, your next Mercury birthday is never more than 88 days away. On Mars you get a birthday roughly every 23 months. On Jupiter you celebrate about once every 12 Earth years, and on Saturn about once every 29. The calculator gives you the exact date for each one.
What is a Saturn return?
Saturn takes about 29.5 Earth years to orbit the Sun. Around age 29, Saturn arrives back in the same part of the sky where it was when you were born. Astrologers call this your Saturn return and link it to big life changes in your late twenties. In astronomy terms, it’s simply your first birthday on Saturn. Your second one arrives at about 59. The milestones section of the calculator gives you both dates.
Why isn’t the Moon on the list?
The Moon travels around the Sun together with Earth, so a year on the Moon is the same length as a year on Earth. Your age on the Moon is your Earth age. What does change is the day: from one sunrise to the next on the Moon takes about 29.5 Earth days.
How old would you be on an exoplanet?
Exoplanets are planets that orbit stars other than our Sun. Some of them circle their star in just a few days, so you’d be extremely old by their calendar.
- Proxima Centauri b, the nearest known exoplanet at 4.2 light-years, has a year of 11.2 days. A 30-year-old would be about 980 there.
- TRAPPIST-1e, an Earth-sized world in its star’s habitable zone, has a year of 6.1 days.
- 51 Pegasi b, the first planet ever found around a Sun-like star, finishes an orbit in 4.2 days. A 30-year-old would be over 2,500.
- LHS 1140 b, a rocky super-Earth 48 light-years away, has a year of 24.7 days. Read about the first atmosphere found on LHS 1140 b.
Frequently asked questions
How old would a 20-year-old be on Mars?
About 10.6 Mars years. A Mars year is 687 Earth days, roughly 1.88 Earth years, so you divide your Earth age by 1.88.
How long is one year on each planet?
Mercury 88 days, Venus 225 days, Earth 365.25 days, Mars 687 days, Jupiter 11.9 years, Saturn 29.5 years, Uranus 84 years and Neptune 164.8 years, all in Earth time.
Which planet matures at 42?
Uranus. It takes 84 years to orbit the Sun, so at about 42 it has travelled halfway around since you were born. Astrologers call this the Uranus opposition and link it to midlife. Astronomically, you turn half a year old on Uranus.
On which planet would I be the oldest?
Mercury, within our Solar System. A 30-year-old is about 125 Mercury years old. On exoplanets with years lasting only a few days, such as 51 Pegasi b, the same person would be over 2,500.
On which planet would I be the youngest?
Neptune. One Neptune year lasts almost 165 Earth years, so everyone alive today is less than one Neptune year old.
Is my age on the Moon different?
No. The Moon orbits the Sun together with Earth, so a Moon year is the same as an Earth year. Only the length of a day is different, about 29.5 Earth days.