Age on Other Planets Calculator
Enter your date of birth and see how old you are in Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto years, using the orbit periods NASA publishes. For each world you get your age to two decimals, the birthdays you have already had and the date of the next one. Free, no sign-up, and nothing leaves your browser.
Your age on Mars
14.24
Mars years old
14
Birthdays so far
686.98 Earth days
One Mars year
26 y 9 m 15 d
Your age on Earth
9,785
Days lived
Your age on every planet
| Planet | Year length (Earth days) | Your age (years) | Birthdays | Next birthday |
|---|---|---|---|---|
| Mercury | 87.969 | 111.23 | 111 | Dec 23, 2026 (in 68 days) |
| Venus | 224.701 | 43.55 | 43 | Jan 26, 2027 (in 102 days) |
| Earth | 365.2425 | 26.79 | 26 | Jan 1, 2027 (in 77 days) |
| Mars | 686.98 | 14.24 | 14 | Mar 19, 2028 (in 520 days) |
| Jupiter | 4,332.589 | 2.26 | 2 | Aug 3, 2035 (in 3,213 days) |
| Saturn | 10,755.699 | 0.91 | 0 | Jun 13, 2029 (in 971 days) |
| Uranus | 30,685.4 | 0.32 | 0 | Jan 5, 2084 (in 20,900 days) |
| Neptune | 60,189.018 | 0.16 | 0 | Oct 16, 2164 (in 50,404 days) |
| Pluto | 90,560 | 0.11 | 0 | Dec 12, 2247 (in 80,775 days) |
Each planet's year is its sidereal orbit period from NASA's Planetary Fact Sheets, and Earth years are 365.2425 days. Pluto is a dwarf planet. Birthdays on other planets are rounded to the nearest whole day, and the time of day you were born is ignored.
How to Use the Age on Other Planets Calculator
- 1. Enter your date of birth. Use the date picker or type year, month and day. The calculator opens on a sample birthday so you can see how the results look.
- 2. Choose the date to measure to. It starts as today's date. Change it to find your age on any past or future day, for example the day a spacecraft arrives at a planet.
- 3. Pick a planet for the headline. The big box shows your age there, the whole birthdays you have had, the length of that planet's year and your age on Earth in years, months and days.
- 4. Read the table. Every planet has a row with its year length, your age, your birthdays so far and the date of the next one. The row you picked is highlighted.
How Your Planetary Age Is Calculated
A year is the time a planet takes to go once round the Sun, so your age on a planet is simply the number of days you have lived divided by the length of that planet's year in days. The calculator counts whole days between your two dates, then divides by each planet's sidereal orbit period: the time to return to the same position against the fixed stars, as listed on NASA's Planetary Fact Sheets. Your age in Earth years uses the average Gregorian year of 365.2425 days, and your Earth birthdays follow the ordinary calendar.
| Planet | Year (Earth days) | Year (Earth years) |
|---|---|---|
| Mercury | 87.969 | 0.241 |
| Venus | 224.701 | 0.615 |
| Earth | 365.2425 | 1.000 |
| Mars | 686.98 | 1.881 |
| Jupiter | 4,332.589 | 11.86 |
| Saturn | 10,755.699 | 29.448 |
| Uranus | 30,685.4 | 84.014 |
| Neptune | 60,189.018 | 164.792 |
| Pluto | 90,560 | 247.945 |
A Worked Example
Someone born on 1 January 2000 has lived 9,785 days by 16 October 2026, which is 26 years, 9 months and 15 days on Earth. Dividing 9,785 by each planet's year gives the ages below. Their next Mercury birthday is on 23 December 2026, 68 days away, while their first Saturn birthday will not come until 13 June 2029.
| Planet | Age | Birthdays so far | Next birthday |
|---|---|---|---|
| Mercury | 111.23 | 111 | 23 Dec 2026 |
| Venus | 43.55 | 43 | 26 Jan 2027 |
| Earth | 26.79 | 26 | 1 Jan 2027 |
| Mars | 14.24 | 14 | 19 Mar 2028 |
| Jupiter | 2.26 | 2 | 3 Aug 2035 |
| Saturn | 0.91 | 0 | 13 Jun 2029 |
| Uranus | 0.32 | 0 | 5 Jan 2084 |
| Neptune | 0.16 | 0 | 16 Oct 2164 |
| Pluto | 0.11 | 0 | 12 Dec 2247 |
The Earth age of 26.79 is the days lived divided by 365.2425, the same span as the calendar's 26 years, 9 months and 15 days written as a decimal. The birthday dates are rounded to whole days, so a Mars birthday is the day on which your age first reaches a whole number of Martian years.
Some Odd Consequences
- Mercury makes you old fast. Its year is 88 days, so you would have a birthday about every 12 weeks and be roughly four times your Earth age.
- Uranus birthdays are rare and Neptune ones impossible. Uranus's year is 84 Earth years and Neptune's 164.8, longer than any human life. Neptune, discovered in 1846, completed its first orbit since discovery in July 2011.
- A Venus day is longer than a Venus year. Venus turns once in about 243 Earth days but orbits in 225, which is why this tool counts years, not days.
- Mars years are close to two Earth years. A Martian year is 686.98 Earth days, or about 668.6 Martian days (sols) of 24 h 39 min 35 s.
Limits
The time of day you were born is ignored, so a birthday can be a day out either way. Orbit periods are long-term averages: real orbits wobble slightly with the pull of the other planets, which matters only for dates centuries away. Pluto is a dwarf planet, and Ceres, Eris and other minor worlds are not included. A planetary year says nothing about seasons: Uranus's tilt gives it quarter-year winters lasting about 21 Earth years.
Frequently Asked Questions
- How do I calculate my age on Mars?
- Count the days you have lived and divide by 686.98, the length of a Martian year in Earth days. Someone aged 26.79 Earth years has lived about 9,785 days, which is 14.24 Mars years. The calculator does the date arithmetic for you, including leap years.
- How old am I on Jupiter?
- Divide your age in Earth years by 11.86, since Jupiter takes 4,332.589 Earth days to orbit the Sun. Even a person of 100 would be only 8.43 Jupiter years old, and a 10-year-old has not yet had a first birthday there.
- Why is my age on Mercury so high?
- Mercury is closest to the Sun and moves fastest, completing an orbit in just 87.969 Earth days. In one Earth year you pass 4.15 Mercury years, so your age there is about 4.15 times your age on Earth.
- Which orbit period does the calculator use?
- The sidereal orbit period from NASA's Planetary Fact Sheets: the time for a planet to return to the same position against the stars. Earth is the exception. Its years are 365.2425 days, the Gregorian average, so Earth ages match your ordinary birthday count.
- When is my next birthday on another planet?
- It falls one planetary year after your last one. The calculator multiplies the orbit period by your next whole birthday number, adds it to your date of birth and rounds to the nearest day. The table shows that date and the number of Earth days until it.
- Does it count the time of day I was born?
- No. It works in whole days between two dates, so results can be off by up to a day. For a cosmic birthday party, that is more than close enough.