Weight Calculator
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Results
Weight on Earth: 150 lbf for a mass of 150 lb
| Location | Gravity (m/s²) | Weight (N) | Weight (lbf) | Scale reading (lb) |
|---|---|---|---|---|
| Mercury | 3.7 | 251.7 | 56.59 | 56.59 |
| Venus | 8.9 | 605.5 | 136.1 | 136.1 |
| Earth | 9.80665 | 667.2 | 150 | 150 |
| Moon | 1.6 | 108.9 | 24.47 | 24.47 |
| Mars | 3.7 | 251.7 | 56.59 | 56.59 |
| Jupiter | 23.1 | 1,572 | 353.3 | 353.3 |
| Saturn | 9.0 | 612.3 | 137.7 | 137.7 |
| Uranus | 8.7 | 591.9 | 133.1 | 133.1 |
| Neptune | 11.0 | 748.4 | 168.3 | 168.3 |
| Pluto | 0.7 | 47.63 | 10.71 | 10.71 |
Gravity values are NASA's planetary fact sheet figures at the equator, including the effect of rotation; for Jupiter, Saturn, Uranus and Neptune they apply at the 1-bar level in the atmosphere, as these planets have no solid surface. Earth uses standard gravity, 9.80665 m/s².
How to use the weight calculator
- Enter a mass and choose its unit. Your bathroom-scale reading works: a scale shows your mass, worked out from your weight on Earth.
- Pick a location, or choose "Other" to type any gravitational acceleration, for example from a physics problem.
- Choose the force unit. The table under the results shows the same mass on all ten bodies, both as a force and as what an Earth scale would read there.
Weight formula
1 N = 1 kg·m/s²
1 lbf = 4.448222 N · 1 kgf = 9.80665 N
Weight (W) is the force of gravity on a mass (m). It equals the mass times the local gravitational acceleration (g). In SI units the mass is in kilograms, g is in meters per second squared, and the weight comes out in newtons. Standard gravity, gₙ = 9.80665 m/s², is the internationally agreed value for Earth. The pound-force and the kilogram-force are defined as the weight of one pound or one kilogram at standard gravity, which is why a 1 kg bag of sugar "weighs 1 kg" in everyday speech.
Worked examples
- On Earth: a 70 kg person weighs 70 × 9.80665 = 686.5 N, or 154.3 lbf.
- On the Moon: with g = 1.6 m/s², the same person weighs 112 N. An Earth bathroom scale would read 11.4 kg, even though the mass is still 70 kg.
- On Mars: someone whose scale reads 150 lb at home would see about 56.6 lb on Mars (252 N), because Mars' gravity is 37.7% of Earth's. On Jupiter's cloud tops the 70 kg person would weigh 1,617 N.
Your weight on other planets
Gravity values are from the NASA Space Science Data Coordinated Archive planetary fact sheet: the acceleration at the equator, including the effect of the planet's spin, rounded to 0.1 m/s². The four giant planets have no solid surface, so their value is given at the level where the atmospheric pressure is 1 bar.
| Location | Gravity (m/s²) | Compared with Earth | 70 kg person reads | 150 lb person reads | Force on 70 kg |
|---|---|---|---|---|---|
| Mercury | 3.7 | 0.377 × | 26.4 kg | 56.6 lb | 259 N |
| Venus | 8.9 | 0.908 × | 63.5 kg | 136.1 lb | 623 N |
| Earth | 9.80665 | 1 × | 70 kg | 150 lb | 686 N |
| Moon | 1.6 | 0.163 × | 11.4 kg | 24.5 lb | 112 N |
| Mars | 3.7 | 0.377 × | 26.4 kg | 56.6 lb | 259 N |
| Jupiter * | 23.1 | 2.356 × | 164.9 kg | 353.3 lb | 1,617 N |
| Saturn * | 9.0 | 0.918 × | 64.2 kg | 137.7 lb | 630 N |
| Uranus * | 8.7 | 0.887 × | 62.1 kg | 133.1 lb | 609 N |
| Neptune * | 11.0 | 1.122 × | 78.5 kg | 168.3 lb | 770 N |
| Pluto | 0.7 | 0.071 × | 5 kg | 10.7 lb | 49 N |
* Measured at the 1-bar pressure level, not a surface.
Why weight changes but mass doesn't
Mass measures how much matter an object contains and how hard it is to accelerate, and it is the same wherever the object goes. Weight depends on how strongly the local planet or moon pulls, which depends on that body's mass and radius. The Moon has far less mass than Earth, so its surface gravity is only about a sixth of ours. Jupiter is enormous, so even at its cloud tops gravity is more than twice Earth's.
Even on Earth, g isn't perfectly constant. NASA gives 9.780 m/s² at the equator and 9.832 m/s² at the poles, because the Earth bulges at the equator and spins. That difference of about half a percent is why precision scales are calibrated where they are used.
Common mistakes
- Mixing pounds and pounds-force. The pound (lb) is a mass; the pound-force (lbf) is the weight of one pound at standard gravity. In physics problems, convert pounds to kilograms before multiplying by g in m/s².
- Using 10 m/s² for g. It is a handy estimate, but it overstates weights by about 2%.
- Forgetting direction. Weight is a force that points toward the center of the planet; on a slope, only part of it pushes into the surface.
To find a mass from a material and its size, use the mass calculator; for density, mass or volume, the density calculator.
Frequently asked questions
How do you calculate weight from mass?
Multiply the mass by the gravitational acceleration: W = m × g. With standard gravity (9.80665 m/s²), a 70 kg person weighs 70 × 9.80665 = 686.5 N, which is about 154.3 pounds-force.
How much would I weigh on the Moon?
The Moon's surface gravity is about 1.6 m/s², roughly 16% of Earth's. A 70 kg person would weigh about 112 N there, and an Earth bathroom scale would read about 11.4 kg (or 24.5 lb for someone who reads 150 lb at home).
What would I weigh on Mars and Jupiter?
Mars' gravity is about 3.7 m/s², so a scale that reads 150 lb on Earth would show about 56.6 lb on Mars. Jupiter's is about 23.1 m/s² at its cloud tops, so the same person would read about 353 lb.
Is weight measured in kilograms or newtons?
Scientifically, weight is a force and is measured in newtons (or pounds-force). Kilograms and pounds measure mass. Everyday scales show kilograms or pounds because they divide the measured force by Earth gravity.
What is the difference between a pound and a pound-force?
A pound (lb) is a unit of mass, exactly 0.45359237 kg. A pound-force (lbf) is the weight of one pound at standard gravity, about 4.448 N. On Earth the numbers match, which is why the two are often confused.