Why your weight changes from planet to planet
What a bathroom scale shows is not your mass but the force with which a planet pulls you down, converted back into pounds or kilograms as if you were on Earth. Your mass never changes, but surface gravity does: it depends on a planet’s mass and radius. On the Moon gravity is about a sixth of Earth’s; on Jupiter, two and a half times more.
The formula
Weight on a planet = weight on Earth × (surface gravity of the planet ÷ 9.80665 m/s²)
The calculator applies the surface gravity of each body, using values published by NASA. For the gas giants, which have no solid surface, gravity is given at the level where the atmospheric pressure equals Earth’s sea-level pressure, roughly the top of the clouds.
Worked example
You weigh 160 lb on Earth. On a scale elsewhere in the solar system you would read:
| Body | Surface gravity | Your weight |
|---|---|---|
| Mercury | 3.70 m/s² | 60.4 lb |
| Venus | 8.87 m/s² | 144.7 lb |
| The Moon | 1.62 m/s² | 26.4 lb |
| Mars | 3.71 m/s² | 60.5 lb |
| Jupiter | 24.79 m/s² | 404.5 lb |
| Saturn | 10.44 m/s² | 170.3 lb |
| Uranus | 8.69 m/s² | 141.8 lb |
| Neptune | 11.15 m/s² | 181.9 lb |
| Pluto | 0.62 m/s² | 10.1 lb |
As a force, your weight on Earth is about 712 newtons.
Surprising results
- Saturn is 95 times more massive than Earth, yet you would weigh only about 7% more there, because its radius is so large that its cloud tops are far from its center.
- Mercury and Mars give almost the same weight. Mercury is smaller, but it is much denser, with a big iron core.
- Venus is close to Earth’s size and mass, so you would weigh about 90% of your Earth weight, though its crushing atmosphere would be the real problem.
What it would feel like
On the Moon, astronauts could carry heavy backpacks with ease and jumped about six times higher than on Earth, but their mass, and so their inertia, was unchanged: stopping a moving object took the same effort as on Earth. On Jupiter, standing would feel like carrying one and a half extra people on your shoulders.
Mass and weight in physics
In physics, weight is a force measured in newtons, W = mg. Everyday scales display kilograms or pounds by dividing that force by Earth’s standard gravity. This calculator follows the everyday convention so that the results read like a scale, and also shows your Earth weight in newtons.