Weight Calculator
Weight is the force gravity exerts on your mass, so it changes from world to world while your mass stays the same. Enter your mass below to see your weight on Earth, the Moon, Mars, Jupiter, and more — in newtons, pounds-force, and kilograms-force.
Mass versus weight
These two words are often used interchangeably in daily life, but in physics they mean different things. Mass is the quantity of matter in an object — it is the same on Earth, on the Moon, or floating in space. Weight is a force: the pull of gravity on that mass, given by W = m × g. Because the gravitational acceleration g differs from place to place, your weight changes even though your mass does not. Astronauts on the Moon still have the same mass, but weigh about one-sixth as much, which is why they can bounce so easily.
How it’s calculated
The calculator converts your mass to kilograms, then multiplies by the surface gravitational acceleration g for the selected body to get weight in newtons (W = m × g). It converts that force to pounds-force by dividing by 4.44822, and to kilograms-force by dividing by 9.80665. Gravity values used: Earth 9.807, Moon 1.62, Mars 3.71, Jupiter 24.79, and the others as listed in the picker (surface values in m/s², from NASA planetary fact sheets).
Values are nominal surface gravities. Gas giants have no solid surface, so their figures are quoted at the 1-bar cloud level, and local gravity on any world varies slightly with latitude and altitude.
Gravity by world
| Body | g (m/s²) | vs. Earth |
|---|---|---|
| Sun | 274 | 27.9× |
| Jupiter | 24.79 | 2.53× |
| Neptune | 11.15 | 1.14× |
| Saturn | 10.44 | 1.06× |
| Earth | 9.807 | 1.00× |
| Venus | 8.87 | 0.90× |
| Uranus | 8.69 | 0.89× |
| Mars | 3.71 | 0.38× |
| Mercury | 3.70 | 0.38× |
| Moon | 1.62 | 0.17× |
| Pluto | 0.62 | 0.06× |
Surface gravities from NASA planetary fact sheets; gas-giant values at the 1-bar level.
Worked example
A person with a mass of 70 kg weighs 70 × 9.807 = 686 N on Earth, which is about 154 lbf or 70 kgf. On the Moon (g = 1.62) the same person weighs 70 × 1.62 = 113 N — roughly 25 lbf, about one-sixth of their Earth weight. On Mars they would weigh about 260 N (58 lbf).
Common mistakes
- Saying an object "weighs 70 kg" — kilograms measure mass; the weight is a force in newtons or pounds-force.
- Assuming a scale would read the same on the Moon; it would show about one-sixth, because it measures force.
- Confusing pounds-mass with pounds-force; they are numerically equal only under Earth gravity.
- Using g = 9.8 for other planets — each world has its own gravitational acceleration.
Where it is used
- Physics homework converting between mass and weight.
- Understanding astronaut experiences and space-mission planning.
- Engineering, where structural loads are forces (newtons), not masses.
- Curiosity — seeing how much you would weigh across the solar system.
Frequently asked questions
What is the difference between mass and weight?
Mass is the amount of matter in an object and stays the same everywhere. Weight is the force gravity exerts on that mass, W = m × g, so it changes with the local gravity. A 70 kg person has a mass of 70 kg on Earth and on the Moon, but weighs about 686 N on Earth and only 113 N on the Moon.
How do you convert mass to weight?
Multiply mass in kilograms by the local gravitational acceleration g (about 9.807 m/s² on Earth) to get weight in newtons: W = m × g. On the Moon g is about 1.62 m/s², on Mars about 3.71, and on Jupiter about 24.79 m/s².
What is a newton versus a pound-force?
Both are units of force. One newton (N) is the force that accelerates 1 kg at 1 m/s². One pound-force (lbf) is the weight of one pound-mass under standard Earth gravity and equals about 4.448 newtons. A kilogram-force (kgf) is the weight of 1 kg on Earth, about 9.807 N.
Why would I weigh more on Jupiter?
Jupiter is far more massive than Earth, so its surface gravity is roughly 2.5 times Earth’s. Your mass would not change, but the stronger pull means the force on you — your weight — is about 2.5 times larger. On the Moon the opposite happens: weaker gravity, so about one-sixth the weight.
Does a scale measure mass or weight?
A spring or digital bathroom scale measures force (weight) and then divides by Earth’s gravity to display an estimated mass in kilograms or pounds. On another planet the same scale would read a different number even though your mass is unchanged, because it assumes Earth gravity.