SPACE ATLASSTUDENT REFERENCE · GRADES 4–8
Solar system · Question

Age on other planets calculator: how old would you be?

A "year" just means one full orbit around the Sun — and that takes wildly different amounts of time depending which planet you're standing on. Enter your age below to find out.

Visual model

Your age, recalculated.

years old on Earth
Mercury
50
Mercury years old
Venus
19
Venus years old
Earth
12
Earth years old
Mars
6.4
Mars years old
Jupiter
1.0
Jupiter years old
Saturn
0.4
Saturn years old
Uranus
0.1
Uranus years old
Neptune
0.1
Neptune years old
Measurable fact

Orbital periods, in Earth time.

  • 88 Earth daysMercury's orbital period (one "year")
  • 225 Earth daysVenus's orbital period (one "year")
  • 1.0 Earth yearsEarth's orbital period (one "year")
  • 1.9 Earth yearsMars's orbital period (one "year")
  • 11.9 Earth yearsJupiter's orbital period (one "year")
  • 29.5 Earth yearsSaturn's orbital period (one "year")
  • 84.0 Earth yearsUranus's orbital period (one "year")
  • 164.8 Earth yearsNeptune's orbital period (one "year")

Why does an outer planet's year grow so quickly?

Explore Kepler's third law: for planets around the Sun, orbital period squared is proportional to the semi-major axis cubed. Choose a planet to compare an idealized prediction with NASA's rounded orbital period.

Relationship between the size of a planet's orbit and the length of its year A logarithmic-logarithmic plot of Kepler's third law, orbital period in Earth years against orbital semi-major axis in astronomical units. Choosing a planet moves an observation marker over the predicted trend. 0.3 AU 3 AU 35 AU Orbital semi-major axis · logarithmic AU scale Year length · log scale 1 yr 10 yr 100 yr Idealized Kepler curve · T² = a³

On small screens, scroll the plot sideways to inspect its logarithmic labels. The numbers below remain fully visible.

Earth: about 1 AU from the Sun; a year is about 1 Earth year. Predicted by Kepler's law: 1 Earth year.

These axes are logarithmic, not equally spaced in AU or years. The plot shows the ideal two-body Sun–planet approximation, not orbital position, speed or inclination. Distances are approximate semi-major axes; periods use NASA rounded values, so prediction and published period can differ slightly.

Evidence: NASA — Orbits and Kepler's Laws and NASA Planetary Fact Sheet. The original eight-planet period list above remains readable without JavaScript.

How it works

Same elapsed time, different length of a year.

The calculator changes the unit used to count your age; it does not change how much time has actually passed.

Formula

Earth age × 365.25 ÷ planet year

First convert your Earth age to Earth days, then divide by that planet's orbital period in days. A shorter orbit produces more planet-years in the same elapsed time.

Example

12 Earth years ≈ 6.4 Mars years

Mars takes about 687 Earth days to orbit the Sun, so a 12-year-old on Earth has lived through only about 6.4 Martian years.

Meaning

Your biology does not change

This is a calendar comparison, not a claim that people age faster or slower on different planets. The same elapsed time is being counted with different orbital clocks.

Misconception check

Quick check.

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Go deeper

Keep exploring.

Orbits

Why don't planets fall into the Sun?

What actually keeps a planet orbiting for that long.

Gravity and orbits ↗