Hong Life CalculatorsUnderstanding the weight on other planets calculator — concept and principle
Your mass stays the same wherever you go, but what a scale reads depends on the local pull of gravity. This calculator converts your Earth weight into what a bathroom scale would show on the Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, using surface gravities from NASA. It is a favourite for science lessons and curious minds.
How it is calculated
Weight on a body = Earth weight × gbody ÷ 9.80665
- Earth weight is entered in kg or lb; the result is in the same unit, as a scale calibrated on Earth would show it.
- Surface gravities (m/s²): Moon 1.62, Mercury 3.70, Venus 8.87, Mars 3.73, Jupiter 23.12, Saturn 8.96, Uranus 8.69, Neptune 11.00, Pluto 0.62.
- 9.80665 m/s² is Earth's standard gravity.
The principle
Weight is the force of gravity on your mass, W = m × g. A bathroom scale actually measures that force but is calibrated to display kilograms or pounds assuming Earth gravity. Take it to Mars, where g is about 38 % of Earth's, and it will show about 38 % of your usual number even though your body has not changed. Surface gravity depends on a body's mass and radius: g = GM ÷ r². Jupiter is enormously massive but also very large, so its gravity is only about 2.4 times Earth's. The giant planets have no solid surface, so their values are given where the atmospheric pressure is 1 bar.
Worked example
Default inputs: Earth weight 70, headline body Mars.
- Ratio for Mars = 3.73 ÷ 9.80665 = 0.3804.
- Weight on Mars = 70 × 0.3804 = 26.6; gravity there = 3.73 m/s².
- Moon: 70 × 1.62 ÷ 9.80665 = 11.6.
- Mercury 26.4, Venus 63.3, Jupiter 165, Saturn 64, Uranus 62, Neptune 78.5, Pluto 4.4.
| Your weight on Earth (kg or lb) | Weight on the chosen body |
|---|---|
| 17.5 | 6.7 |
| 35 | 13.3 |
| 52.5 | 20 |
| 70 | 26.6 |
| 87.5 | 33.3 |
| 105 | 39.9 |
| 140 | 53.2 |
How to read the result
On the Moon you would weigh about one-sixth of your Earth weight, which is why astronauts could bound across the surface. Mercury and Mars feel similar to each other at about 38 %. Venus, Saturn and Uranus are surprisingly close to Earth. Jupiter would make standing tiring. Remember that your mass, and therefore your inertia, is unchanged: pushing a heavy cart on the Moon is just as hard to start moving as on Earth.
Common mistakes
- Thinking your mass changes; only the scale reading does.
- Expecting much higher weight on Saturn because it is huge; its low density keeps surface gravity near Earth's.
- Treating gas-giant values as standing on a surface; there is none.
Frequently asked questions
How much would I weigh on the Moon?
About 16.5 % of your Earth weight; 70 kg reads about 11.6 kg.
Why is Saturn's gravity so close to Earth's?
Saturn is very massive but also very large, and gravity falls with the square of the radius.
Is weight in kg correct?
Strictly, weight is a force in newtons, but scales display kg assuming Earth gravity.
Which planet has the strongest gravity?
Jupiter, at about 23.1 m/s² at the 1-bar level.
Sources: NASA NSSDCA Planetary Fact Sheets (D. R. Williams, NASA Goddard) · BIPM, The International System of Units (SI Brochure), 9th edition (standard gravity)