Why do I weigh less on the Moon? Does my mass change?

Mass, the amount of matter in you, is the same everywhere. A scale measures the force you press on it, mg. The Moon's surface gravity is about 1.62 m/s², 16.5% of Earth's, so a 150 lb person reads about 25 lb there, yet is just as hard to push sideways. The tool scales readings by the ratio to Earth's gravity, so Earth shows exactly the weight you entered.

How is surface gravity calculated?

With Newton's law, g = GM/R², using NASA/JPL values of GM and radius. Rocky bodies use the mean radius; Jupiter, Saturn, Uranus and Neptune have no solid surface, so by convention the 1-bar equatorial radius is used. Rotation and terrain are ignored, which is why Earth comes out at 9.82 m/s² while the real value is about 9.78 at the equator and 9.83 at the poles.

Could I really jump that high on the Moon or Ceres?

With the same take-off speed, jump height h = v²/(2g) is inversely proportional to gravity: about 6 times higher on the Moon and about 35 times on Ceres, with hang time growing by the same factor. In practice heavy spacesuits limited Apollo astronauts to jumps of a few tens of centimetres. On a small enough body your take-off speed could exceed the escape velocity and you would never come back; the tool flags that case.

Why is gravity on Saturn and Uranus close to Earth's?

Surface gravity depends on M/R², not mass alone. Saturn has 95 times Earth's mass but 9.4 times its radius, and 95/9.4² ≈ 1.07, so gravity at the cloud tops is about Earth's. Uranus has 14.5 times the mass and 4 times the radius, giving about 0.9 g. Likewise Ganymede is larger than Mercury but much less dense, with only about 40% of Mercury's gravity.

Can I trust the white dwarf and neutron star numbers?

The white dwarf is Sirius B (1.02 solar masses, radius about 5,800 km); its surface gravity is about 400,000 times Earth's and Newton's law still works well. The neutron star is 1.4 solar masses with a 12 km radius, giving roughly 10¹¹ times Earth's gravity, but there GM/(Rc²) ≈ 0.17, so general relativity matters a lot and the Newtonian escape velocity of 0.59c is only an order-of-magnitude guide. Either way, you would be flattened to a layer thinner than an atom.

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⚖️Weight on Other Planets Calculator - Moon, Mars, Jupiter and Beyond

Enter your weight on Earth and see what a bathroom scale would read on every planet from Mercury to Neptune, on Pluto, the Moon, the Sun, the big moons of Jupiter and Saturn, Ceres, and even a white dwarf and a neutron star. Surface gravity comes from g = GM/R² with NASA/JPL data, and the tool also tells you how high you could jump, how long a 1 m fall takes, how far you could throw a ball and the escape velocity. Little figures squash or stretch with gravity, a side-by-side jump animation compares any body with Earth, and one click copies the results to share.

Free · No sign-up · Runs in your browserLast updated: 2026-10-29

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How to use Your Weight on Other Planets

1Enter your weight on Earth and choose kilograms, pounds or jin
2Optionally set how high you can jump and how far you can throw on Earth
3Read the scale readings and fun facts in the comparison view; switch to a log scale or add the white dwarf and neutron star
4Open the full data table or jump side by side with Earth, then press Copy results to share

FAQ

Why do I weigh less on the Moon? Does my mass change?: Mass, the amount of matter in you, is the same everywhere. A scale measures the force you press on it, mg. The Moon's surface gravity is about 1.62 m/s², 16.5% of Earth's, so a 150 lb person reads about 25 lb there, yet is just as hard to push sideways. The tool scales readings by the ratio to Earth's gravity, so Earth shows exactly the weight you entered.
How is surface gravity calculated?: With Newton's law, g = GM/R², using NASA/JPL values of GM and radius. Rocky bodies use the mean radius; Jupiter, Saturn, Uranus and Neptune have no solid surface, so by convention the 1-bar equatorial radius is used. Rotation and terrain are ignored, which is why Earth comes out at 9.82 m/s² while the real value is about 9.78 at the equator and 9.83 at the poles.
Could I really jump that high on the Moon or Ceres?: With the same take-off speed, jump height h = v²/(2g) is inversely proportional to gravity: about 6 times higher on the Moon and about 35 times on Ceres, with hang time growing by the same factor. In practice heavy spacesuits limited Apollo astronauts to jumps of a few tens of centimetres. On a small enough body your take-off speed could exceed the escape velocity and you would never come back; the tool flags that case.
Why is gravity on Saturn and Uranus close to Earth's?: Surface gravity depends on M/R², not mass alone. Saturn has 95 times Earth's mass but 9.4 times its radius, and 95/9.4² ≈ 1.07, so gravity at the cloud tops is about Earth's. Uranus has 14.5 times the mass and 4 times the radius, giving about 0.9 g. Likewise Ganymede is larger than Mercury but much less dense, with only about 40% of Mercury's gravity.
Can I trust the white dwarf and neutron star numbers?: The white dwarf is Sirius B (1.02 solar masses, radius about 5,800 km); its surface gravity is about 400,000 times Earth's and Newton's law still works well. The neutron star is 1.4 solar masses with a 12 km radius, giving roughly 10¹¹ times Earth's gravity, but there GM/(Rc²) ≈ 0.17, so general relativity matters a lot and the Newtonian escape velocity of 0.59c is only an order-of-magnitude guide. Either way, you would be flattened to a layer thinner than an atom.

Features

18 bodies: eight planets, the Sun, Moon, Pluto, Ceres, four large moons, a white dwarf and a neutron star
g = GM/R² from NASA/JPL GM and radii, with notes on equatorial versus mean radius
Scale reading, force in newtons, jump height, 1 m fall time, throwing range and escape velocity
Bar chart with figures that squash or stretch, plus a log-scale option
Real-time jump animation next to Earth, with adjustable speed
One-click copy of a shareable text summary

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