Why does my weight change but not my mass?

Mass is the amount of matter in your body and never changes. Weight is the force of gravity pulling on that mass, so it changes with each body's surface gravity.

Which body's gravity is used?

Each figure uses the body's surface gravity relative to Earth, for example Mars is about 0.377 g and Jupiter about 2.528 g.

Is my weight sent anywhere?

No — every calculation runs locally in your browser and nothing is uploaded.

Planet Weight Calculator

See how much you would weigh on every planet, the Moon and the Sun.

How much would you weigh on another planet?

Your mass is fixed, but your weight depends on the local pull of gravity. Enter your Earth weight and this calculator shows what you would weigh on Mercury, Venus, Mars, the Moon, Jupiter, Saturn, Uranus, Neptune, Pluto and even the Sun — all at once.

Everything runs in your browser. Nothing you type is uploaded.