21 kg — 3.47 kg on the Moon, 7.97 kg on Mars
A body that weighs 21 kg on Earth reads 3.47 kg on the Moon, 7.97 kg on Mars and 53.09 kg on Jupiter. The matter is unchanged; only the pull differs.
On Earth 21 kg
| Weight on other worlds | What the scale reads | Earth = 1 |
|---|---|---|
| the Sun | 586.74 kg | ×27.94 |
| Mercury | 7.92 kg | ×0.377 |
| Venus | 18.99 kg | ×0.904 |
| Earth | 21 kg | ×1 |
| the Moon | 3.47 kg | ×0.165 |
| Mars | 7.97 kg | ×0.379 |
| Jupiter | 53.09 kg | ×2.528 |
| Saturn | 22.36 kg | ×1.065 |
| Uranus | 18.99 kg | ×0.904 |
| Neptune | 23.88 kg | ×1.137 |
| Pluto | 1.33 kg | ×0.063 |
| io | 3.85 kg | ×0.183 |
| europa | 2.81 kg | ×0.134 |
| ganymede | 3.06 kg | ×0.146 |
| callisto | 2.64 kg | ×0.126 |
| titan | 2.9 kg | ×0.138 |
| enceladus | 0.24 kg | ×0.012 |
| triton | 1.67 kg | ×0.079 |
| ceres | 0.58 kg | ×0.028 |
| eris | 1.76 kg | ×0.084 |
| vesta | 0.54 kg | ×0.025 |
- Force of gravity
- 205.9 N
- Jump height goes the other way
- 302.7 cm
The mass stays; only the weight moves
Mass is the matter you are made of; weight is the pull on it. Nobody loses matter by flying to the Moon — only the needle drops to one sixth. That is why physics measures weight in newtons rather than kilograms.
Jump height goes the other way
For the same push, the height you rise is inversely proportional to gravity. A 50 cm jump on Earth becomes over three metres on the Moon — and it does not depend on how much you weigh.
Some of these have no ground
Jupiter, Saturn, Uranus and Neptune have no solid ground; their figures are taken at the cloud tops. The Sun needs no explanation — nothing could stand there, so the number is arithmetic only.
Nearby weights
How to read this
- Scale reading = Earth weight × (that world’s gravity ÷ Earth’s gravity).
- Earth’s gravity is 9.80665 m/s², and every ratio here is measured against it.
- Force in newtons = mass × gravity. A 70 kg person feels about 686 N on Earth.
- Jump height is inversely proportional to gravity, so the Moon lifts you six times higher.
Frequently asked questions
Q. What would 21 kg read on the Moon?
3.47 kg, because lunar gravity is 0.165 of Earth’s.
Q. And on Mars?
7.97 kg. Venus gives 18.99 kg and Jupiter 53.09 kg.
Q. What is that as a force?
On Earth it is 205.9 N — 21 kg of mass times 9.80665.
Q. Have you actually lost anything?
No. The matter is still 21 kg everywhere; only the pull the scale measures changes.