Age on Other Planets Calculator
Enter your Earth age and see how old you would be on every other planet in the Solar System — in local planet-years and in local sidereal days (sols).
Age on Mars
16 years
- ☿ Mercury
- 125 years · 187 days
- ♀ Venus
- 48.8 years · 45 days
- ♂ Mars
- 16 years · 10,680 days
- ♃ Jupiter
- 2.53 years · 26,495 days
- ♄ Saturn
- 1.02 years · 24,679 days
- ♅ Uranus
- 0.36 years · 15,254 days
- ♆ Neptune
- 0.18 years · 16,324 days
- ♇ Pluto
- 0.12 years · 1,716 days
Each planet-year is the time it takes that planet to orbit the Sun once, in Earth days (NASA Planetary Fact Sheet). Earth years are converted to Earth days using the sidereal year (365.25636 d), then divided by each planet's orbital period for years, and by its rotation period for local days.
How to use this calculator
Type your age in Earth years. The calculator returns the equivalent age on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, plus the number of local days (sols) you have lived on each. Decimals are allowed for partial years — enter 30.5 for thirty-and-a-half years.
How the calculation works
Each planet-year is the time the planet takes to orbit the Sun once, measured in Earth days. To convert, the calculator multiplies your Earth age by 365.25636 (one sidereal Earth year), giving the total number of Earth days you have lived, then divides by that planet's orbital period to get planet-years and by its sidereal rotation period (in hours, converted from Earth-hours lived) to get local days. All planetary constants come from the NASA Planetary Fact Sheet. Venus and Uranus rotate retrograde — they still count sunrises, so the calculator uses the absolute rotation period.
Worked example
A 30-year-old on Earth has lived 30 × 365.25636 = 10,957.7 Earth days. Mars takes 686.980 Earth days to orbit the Sun, so age on Mars = 10,957.7 / 686.980 = 15.95 Mars years. Mars's sidereal day is 24.6229 hours, so the same person has lived (10,957.7 × 24) / 24.6229 = 10,680 sols. Mercury, with an 87.969-day year, returns 124.6 Mercurian years — the same span feels eight times longer when measured against Mercury's short orbit.
Frequently asked questions
Why is my Mercury age so much higher than my Earth age?
Mercury orbits the Sun in only 88 Earth days, so it laps the Sun about 4.15 times for every one Earth lap. Your time-lived in seconds does not change, but expressed in Mercurian years (Mercurian orbits) it is roughly 4.15× your Earth age. The further out the planet, the longer its year and so the smaller the equivalent age — Neptune takes 165 Earth years for one orbit, so most humans never live a full Neptunian year.
What is a "sol" and why does the calculator show it?
A sol is one local sidereal day — one full rotation of the planet relative to the stars. Earth's sol is 23.9345 hours (the familiar 24-hour day is the slightly longer solar day, but the difference is under four minutes). Mars's sol is 24.6229 hours, which is why NASA tracks rover ages in sols rather than Earth days. For planets that rotate very slowly — Mercury at 1,408 hours and Venus at 5,833 hours per sol — a single day can be longer than a year, which is why your "days lived" count on those planets is so small.
Which orbital and rotation values does the calculator use?
All values come from the NASA Goddard Planetary Fact Sheet (nssdc.gsfc.nasa.gov/planetary/factsheet/). Orbital periods: Mercury 87.969 d, Venus 224.701 d, Earth 365.25636 d, Mars 686.980 d, Jupiter 4,332.589 d, Saturn 10,759.22 d, Uranus 30,688.5 d, Neptune 60,182 d, Pluto 90,560 d. Sidereal rotation periods in hours: Mercury 1,407.6, Venus 5,832.6 (retrograde), Earth 23.9345, Mars 24.6229, Jupiter 9.9259, Saturn 10.656, Uranus 17.24 (retrograde), Neptune 16.11, Pluto 153.2928. The calculator uses the sidereal Earth year (365.25636 d), not the civil Gregorian average of 365.2425 d, so the ratios stay consistent with NASA's tabulated values.
Why is Pluto included if it is no longer a planet?
The International Astronomical Union reclassified Pluto as a dwarf planet in 2006, but it remains the most familiar object beyond Neptune and still appears in almost every "your age on other planets" page. Pluto is included here for completeness and curiosity. The math works identically: a 248-Earth-year orbit gives one Plutonian year, so a 30-year-old on Earth is only about 0.12 Plutonian years old — barely past Plutonian infancy.
Why are Venus and Uranus rotation periods shown as positive numbers if they rotate backwards?
Venus and Uranus rotate retrograde (opposite to their orbital direction), so the sidereal rotation period is technically negative when signed for direction. The number of sunrises an observer would see per orbit does not depend on the direction of spin — only on how fast the planet turns — so the calculator uses the absolute value of the rotation period. This matches how NASA reports day length in popular references and avoids the confusing "negative days lived" you would get from a naive signed division.
Does this account for the speed of orbit changing over time?
No — orbital periods are treated as constants. In reality, planetary orbits change on geological timescales due to gravitational interactions, the Sun slowly losing mass, and tidal effects, but the changes over a single human lifetime are tens of seconds at most. For a present-day age calculation, treating the orbital period as a fixed mean value is accurate to seven or more significant figures, far more precision than the calculator displays.