🎂 Age on Other Planets

Your age is really just a count of trips around the Sun. Every other planet takes a different amount of time to make that trip, so how old are you really?

🐾 Think of it like dog years, but for planets: this isn't a medical or legal age, and nothing about you actually changes. You're the same age everywhere; these numbers just count how many times each planet has looped the Sun since you were born. Mercury does a lap every 88 days. Neptune takes about 165 of our years to do the same lap. Same you, wildly different math.

🎉 Enter Your Birthdate

We only use this in your browser to do the math; nothing is sent anywhere.

🌌 Your Age, Planet by Planet

📊 Sorted by Age

Log scale: a planet with a shorter year rolls up more birthdays, so the numbers span several orders of magnitude.

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Formula

Ageplanet = Days alive ÷ Orbital periodplanet
Days alive = days elapsed since your birthdate
Orbital periodplanet = time for that planet to complete one full orbit of the Sun, in Earth days

A "birthday" on another planet is just one full lap of the Sun for that planet, so a planet with a short year (like Mercury, 88 Earth days) racks up birthdays fast, while a planet with a long year (like Neptune, ~165 Earth years) might not have seen you have a single one yet. The Moon and Sun are left out here since neither one has its own orbit around the Sun to count years by.