Age, as we know it, is an Earth convention: it counts how many times the Earth has orbited the Sun since your birth. But if you had been Martian — or if future Mars colonists count their lives in Martian years — your age would be considerably different. Mars takes 687 Earth days to complete one full revolutihaveround the Sun, almost twice as long as Earth.

Result: your Martian age is about half your Earth age. A 30-year-old human would only be "16" in Martian years — and would not yet be of voting age on the red planet, if the same rules applied. It is one of the most intuitively surprising calculations you can do with your date of birth.

How does it work?

The calculation is straightforward:

Note: a day on Mars (Martian sol) lasts 24h 37min — almost like on Earth. So Martian days are nearly identical to Earth days. It is the year that is very different, not the day. Astronauts and NASA teams managing Mars rovers actually work in "sols" to track Mars's rhythm.

Concrete examples

This gap has an interesting consequence: Martian "birthdays" come much less frequently. Your 18th Martian birthday (the equivalent of adulthood) would arrive at 33.8 Earth years.

Why it's fascinating

The question of age on other planets is no longer purely theoretical. SpaceX and NASA are actively planning crewed missions to Mars, potentially from 2030. If humans settle there permanently, the question of a dating system will arise concretely: should they adopt the Martian sol, keep the Earth calendar, or invent a hybrid?

NASA already uses Martian sols for its ground operations. The Perseverance rover, for example, has counted its days in sols since landing. The first generations born on Mars might naturally develop a Martian temporal identity — and find the idea of "counting in Earth years" strange.

More philosophically, calculating your age on Mars helps you understand that age is a relative measure, not an absolute one. It measures planetary revolutions, not biological internships. Your body ages at the same rate regardless of which calendar we use to count it.

Did you know?

Seasons exist on Mars, but they are very unequal. Mars's elliptical orbit is more elongated than Earth's. Summer in the Martian southern hemisphere is short and very hot, while winter is long and cold. If you lived near the Martian south pole, you would endure winters of more than 300 consecutive sols (nearly an Earth year) without seeing the Sun at its zenith.
Temperature on Mars ranges from -125°C to +20°C depending on seasand location. Near the equator, a Martian day can reach +20°C in the afternoon, before plunging to -73°C at night. Daily temperature swings are enormous — far more than on Earth, due to the very thin atmosphere that retains little heat.
Olympus Mons, the largest volcano on Mars, rises 21.9 km above the plain. That is almost three times the height of Everest (8.8 km). If you climbed Olympus Mons, you would exit Mars's atmosphere midway — the pressure at the summit is 100 times lower than at the base.

Frequently asked questions

How do I calculate my age on Mars?

Multiply your Earth age by 0.5316 for an approximation of your Martian years. For more precision: divide your age in days by 686.971. For example, 30 years = 10,957 days / 686.971 = 15.95 Martian years.

Does a day last the same time on Mars and on Earth?

Almost. A Martian sol (day on Mars) lasts 24 hours, 37 minutes and 22 seconds — 2.7% longer than an Earth day. Over a Martian year, this gap accumulates: a Martian year contains 668.6 sols. So a Martian year is long in Earth days, but not so much in Martian sols.

Will humans age differently on Mars?

The biology of ageing does not change depending on the planet. But Martian conditions would pose specific challenges: cosmic radiation (less protected by Mars's weak magnetic field), reduced gravity (38% of Earth's gravity, which would weaken muscles and bones), and a lack of vitamins linked to sunlight (much less intense on Mars). Humans on Mars would age biologically at the same rate, but potentially with different pathologies.

Is there an official "Martian calendar"?

Several Martian calendar proposals have been published by researchers and enthusiasts, but none is official. The best known is the "Darian calendar" proposed by Thomas Gangale in the 1980s, which divides the Martian year into 24 months. NASA simply uses sol numbering for its missions.

On which other planet would my age differ most?

On Mercury, a year lasts only 88 Earth days — so you would have about 4 times your Earth age. On Jupiter, a year lasts 4,333 days — you would have only a few "Jovian years" even at 80 Earth years. Venus is peculiar: its "day" is longer than its year! Age on other planets is also explored on StatsMe, including for Jupiter.

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