Weight on Mars, Explained: The Simple Physics
Ask someone what they'd weigh on Mars and you'll usually get a guess. But it's not a guess — it's one line of physics, and once you see it, you can work out your weight on any world in the Solar System in your head. Let's walk through it, then look at the numbers for every planet.
Mass and weight are not the same thing
This is the key idea, and it's simpler than textbooks make it sound. Your mass is the amount of matter in you. It's a property of your body — atoms, muscles, bones — and it does not change when you travel. Your weight is a force: how hard gravity is pulling on that mass. Change the gravity, change the weight. Same you, different pull.
That's why mission scientists talk about astronauts' mass staying constant during a trip to Mars while their weight — the force their boots press into the dirt with — drops to about 38% of what it was on Earth.
The formula (one line)
Weight on Mars = Your Earth weight × (Mars gravity ÷ Earth gravity) = Your weight × 0.377
Mars is smaller and less dense than Earth, so its surface gravity is about 3.71 m/s² versus Earth's 9.81 m/s². Divide those and you get 0.377. That single multiplier does everything.
Worked examples
| Your Earth weight | On Mars (×0.377) | On the Moon (×0.166) | On Jupiter (×2.364) |
|---|---|---|---|
| 50 kg (110 lb) | 18.9 kg | 8.3 kg | 118.2 kg |
| 70 kg (154 lb) | 26.4 kg | 11.6 kg | 165.5 kg |
| 90 kg (198 lb) | 33.9 kg | 14.9 kg | 212.8 kg |
Note: when we say a "26.4 kg weight" on Mars, we mean your body would press on Martian scales with the same force that 26.4 kg presses on Earth scales. Scales are calibrated for Earth's gravity, which is exactly what our Weight on Other Planets calculator simulates.
The full Solar System comparison
| World | Surface gravity | × Earth | 70 kg person weighs |
|---|---|---|---|
| 🌙 Moon | 1.62 m/s² | 0.166 | 11.6 kg |
| ☿ Mercury | 3.70 m/s² | 0.378 | 26.5 kg |
| ♀ Venus | 8.87 m/s² | 0.907 | 63.5 kg |
| 🌍 Earth | 9.81 m/s² | 1.000 | 70.0 kg |
| ♂ Mars | 3.71 m/s² | 0.377 | 26.4 kg |
| ♃ Jupiter | 24.79 m/s² | 2.364 | 165.5 kg |
| ♄ Saturn | 10.44 m/s² | 0.916 | 64.1 kg |
| ♅ Uranus | 8.87 m/s² | 0.889 | 62.2 kg |
| ♆ Neptune | 11.15 m/s² | 1.125 | 78.8 kg |
| (dw) Pluto | 0.62 m/s² | 0.063 | 4.4 kg |
Two surprises people love: Saturn, despite being enormous, would make you lighter than Earth does — it's mostly gas and less dense than water. And the Moon and Mars, despite being very different worlds, pull almost exactly alike from a human-scale point of view.
Why Mars is the "goldilocks" gravity people talk about
At 38% of Earth's pull, Mars sits in a sweet spot often discussed in space exploration: heavy enough that everyday life feels normal, light enough that a loaded astronaut in a 90 kg suit moves easily. NASA's own Mars science missions — from the Pathfinder landers to the Perseverance rover — operate with exactly this physics every day.
Try it yourself
Type your own weight into the Weight on Other Planets calculator and see the whole table update instantly. Then, for the time-based side of space travel, check your age on other planets — or wind down with a round of Astro Dodge, where asteroid gravity is mercifully set to zero.