How Old Are You on Mars?
Calculate your age across the solar system
Calculate your age on every planet in the solar system — from Mercury to Neptune, plus Pluto. Each planet's year is a different length, so your age changes dramatically depending on where you are in the cosmos. Enter your date of birth and instantly see how many planetary years old you are, when your next birthday falls on each world, and fun comparisons across the solar system.
💡 A year on Neptune lasts 165 Earth years — meaning no human has ever lived through a full Neptunian year.
Frequently asked questions
How long is a year on Mars?
A Martian year is 686.97 Earth days — roughly 1.88 Earth years. That means if you are 30 Earth years old, you are about 16 Martian years old. A Martian day, called a sol, is 24 hours and 39 minutes, so daily routines on Mars would feel almost familiar, but birthdays would arrive at half the Earth pace.
How old am I on Jupiter?
Jupiter takes 11.86 Earth years to orbit the Sun, so divide your Earth age by ~12 to get your Jovian age. A 30-year-old human is about 2.5 Jupiter years old. On Saturn (29.5 Earth-year orbit) you would be barely one year old, and on Neptune (165 years) most humans never live to see their first birthday.
Why is each planet's year different?
Kepler's third law states that orbital period scales with the 3/2 power of distance from the Sun. A planet twice as far from the Sun as Earth orbits in 2.83 Earth years. Distant planets travel slower (Neptune's orbital velocity is about 1/6 of Earth's) and over longer paths, so their years stretch dramatically.
Has anyone celebrated a Mars birthday?
No human has yet — but NASA's Curiosity rover marked its first Martian birthday on June 24, 2014, two Earth years after landing. The Perseverance rover and Ingenuity helicopter have similarly tracked their mission anniversaries in sols and Mars years.