Age and Weight on Other Planets Calculator

Updated October 2026 by Elena Stone

Enter your weight and your birthday to see what you would weigh on every planet, how old you would be in each planet’s years and the date of your next birthday there. On Mars you would weigh 38% of what you weigh on Earth, and a 10-year-old would be 5.32 Mars years old.

Your weight on each planet

Your weight on another planet is your weight on Earth multiplied by that planet’s surface gravity, divided by Earth’s gravity (9.81 m/s²). The table shows the result for a person who weighs 100 lb or 50 kg on Earth.

Of the planets, Jupiter pulls hardest: you would weigh 2.53 times as much there. The dwarf planet Pluto pulls least, at 6% of Earth’s gravity. Saturn, Uranus and Neptune are far bigger than Earth but are made mostly of gas and ice, so their gravity at the cloud tops ends up close to ours. Those four giant planets have no solid surface, so their values are measured at the height where the air pressure equals sea-level pressure on Earth.

How old would you be on each planet?

A year is the time a planet takes to go once around the Sun. Mercury does it in 88 Earth days, so you would have a birthday there about every three months. Neptune takes 165 Earth years. It finished its first full orbit since its discovery in 1846 only in 2011.

The calculator gives no age for the Moon or the Sun. The Moon goes around the Sun together with Earth, so its year is the same as ours. The Sun does not orbit anything in the Solar System.

How long is a day on each planet?

A day here means sunrise to sunrise. On Mars it lasts 24 hours and 40 minutes, almost the same as on Earth. A day on Venus lasts 116.75 Earth days. Venus also spins backwards and so slowly that one turn takes 243 Earth days, which is longer than its 225-day year.

How high could you jump on other planets?

If you push off the ground just as hard as you do on Earth, your jump height changes in the opposite direction to gravity. A 0.5 m jump on Earth becomes 3 m on the Moon, 7.9 m on Pluto and 20 cm on Jupiter. The numbers below leave out the weight of a spacesuit.

How to calculate your weight on another planet

Weight is the force of gravity on your mass. Physics classes write it as:

W = m × g

• W is weight in newtons (N)
• m is mass in kilograms (kg)
• g is the surface gravity of the planet in m/s²

Worked example: a student with a mass of 45 kg stands on Mars, where g is 3.71 m/s².

1. W = 45 kg × 3.71 m/s² = 167.0 N
2. On Earth the same student weighs 45 × 9.81 = 441.5 N
3. A bathroom scale on Mars would read 167.0 ÷ 9.81 = 17.0 kg

The shortcut skips newtons. Divide the planet’s gravity by Earth’s to get a ratio, then multiply your Earth weight by it. For Mars the ratio is 3.71 ÷ 9.81 = 0.378, so 45 kg becomes 17.0 kg and 100 lb becomes 37.8 lb. Turn on Homework mode in the calculator to see this working for every planet with your own number.

Mass does not change

The student in the example has a mass of 45 kg on Earth, on Mars and in empty space. Only the weight changes. A bathroom scale measures force and turns it into kilograms by assuming Earth’s gravity, which is why the scale on Mars shows 17.0 kg. When a question asks for weight in kilograms, it means this scale reading.

How to calculate your age on another planet

Multiply your age by the length of an Earth year in days, then divide by the length of the planet’s year in Earth days:

Age on planet = age in Earth years × 365.25 ÷ planet’s year in Earth days

Worked example: a 12-year-old on Mercury is 12 × 365.25 ÷ 87.97 = 49.8 Mercury years old. On Mars the same person is 12 × 365.25 ÷ 686.98 = 6.38 Mars years old.

With a birth date you can be exact: count the days since you were born and divide by the planet’s year. The whole number is your age there. Your next birthday on that planet falls when the count of days reaches the next whole year, and that is the date the calculator shows on each card.

How old is each planet and how much does it weigh?

Earth is 4.54 billion years old. The Sun formed about 4.6 billion years ago and the planets formed from the disk of gas and dust around it within the next 100 million years, so every planet is about 4.5 billion years old. The Moon formed about 4.5 billion years ago, after a body the size of Mars hit the young Earth.

A planet has no weight in the usual sense, because there is nothing for it to rest on. When people ask how much a planet weighs, they mean its mass. Earth’s mass is 5.97 × 10²⁴ kg, or about 6 trillion trillion kilograms.

For how scientists date each planet, see Age of the Planets: How Old Are They?

Calculators for each planet

Each planet also has its own page with the calculator set to that planet and more detail about its gravity or its year.

Weight: Mercury · Venus · the Moon · Mars · Jupiter · Saturn · Uranus · Neptune · the Sun

Age: Mercury · Venus · Mars · Jupiter · Saturn · Uranus · Neptune · Pluto

Frequently asked questions

Sources

Orbit periods, day lengths and masses come from the NASA Space Science Data Coordinated Archive Planetary Fact Sheets. Surface gravity uses the standard values found in most textbooks: 9.81 m/s² for Earth, 3.71 m/s² for Mars and 24.79 m/s² for Jupiter. For Jupiter, Saturn, Uranus and Neptune, gravity is measured at the 1 bar pressure level. NASA’s current fact sheets give a mean gravity for each planet instead, such as 25.92 m/s² for Jupiter, so results based on those differ by up to 7%.