Cosmic Age Again

Cosmic Age

How Old Are You on Other Planets?

A year is one trip around the Sun. Because every planet orbits at a different speed, your age changes depending on which world you ask.

We use this only to do the math — nothing is stored or sent anywhere.
🔒 Private — runs in your browser⚡ Instant results🛰️ Real NASA data

Frequently Asked Questions

Do you store my birth date or any personal data?

No. All calculations happen entirely in your browser using JavaScript. Your birth date is never saved, transmitted to a server, or shared with anyone. The site is 100% safe to use.

How is my age on other planets calculated?

We divide the number of days you have been alive by the length of each planet year in Earth days. Mercury orbits the Sun in 88 days, so a 30-year-old is about 124 Mercury years old.

What is a planetary birthday?

Your planetary birthday on Mars happens each time you complete another Mars orbit — every 687 Earth days. On Mercury, it comes around every 88 days.