Age on Other Planets
Calculate how old you would be on each planet in the solar system based on their orbital periods.
About this tool
Age on Other Planets calculates how many years old you would be on each planet in our solar system, based on how long each planet takes to orbit the sun. Since planets have different orbital periods—Mercury completes an orbit in just 88 days while Neptune takes 165 years—your age is completely different depending on which planet you're on. It's a fun way to explore how relative time and planetary motion work together.
Simply enter your birth date, and the tool instantly shows your age across all eight planets. The calculation works by dividing the number of Earth days you've lived by each planet's orbital period in days. You can see at a glance that you'd be much older on Mercury (which completes many orbits) and much younger on Neptune (which barely completes even one orbit during a human lifetime).
This tool is educational for students learning about the solar system and orbital mechanics, entertaining for anyone curious about space, and a great conversation starter. It works entirely in your browser, so no data is stored or sent anywhere.
Frequently Asked Questions
Code Implementation
from datetime import date
ORBITAL_PERIODS = {
"Mercury": 0.2408467,
"Venus": 0.6151972,
"Earth": 1.0,
"Mars": 1.8808158,
"Jupiter": 11.862615,
"Saturn": 29.447498,
"Uranus": 84.016846,
"Neptune": 164.79132,
}
def age_on_planets(birth_date: date, ref_date: date | None = None) -> dict:
if ref_date is None:
ref_date = date.today()
earth_years = (ref_date - birth_date).days / 365.25
return {
planet: round(earth_years / period, 2)
for planet, period in ORBITAL_PERIODS.items()
}
birth = date(1990, 6, 15)
ages = age_on_planets(birth)
for planet, age in ages.items():
print(f"{planet:8s}: {age:8.2f} years")Comments & Feedback
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