How this calculator works
- Step 1Masskg or lbThe same on every world.
- Step 2Gravityg in m/s²NASA’s figure for the planet or moon.
- Step 3WeightW = m × gA force, in newtons.
Mass is how much matter something has. Weight is the force gravity pulls it with, so it changes from one world to another while the mass stays the same.
A bathroom scale measures that force but is calibrated for Earth. The calculator also shows what the same scale would read elsewhere.
Worked example: 70 kg on Mars
- Weight
m × g- Scale
m × g ÷ 9.8
- Mars gravity3.7 m/s²
- Weight70 × 3.7259.0 N
- In pound-force÷ 4.44858.2 lbf
- Earth scale reads70 × 3.7 ÷ 9.826.4 kg
On Earth the same mass weighs 686.0 N. Mars gravity is about 38% of Earth’s, so the scale shows far less.
Read the result
The same 70 kg would show 11.4 kg on the Moon and 165.0 kg at Jupiter’s cloud tops.
Mass and weight
- MasskgAmount of matter. Does not change with location.
- WeightNForce of gravity on that mass. Changes with g.
Assumptions and limits
- NASA valuesPlanetary Fact Sheet, rounded as published.
- EquatorMeasured at the equator, including rotation.
- Gas giantsAt the 1-bar level; they have no solid surface.
- Not exactLocal gravity varies with height and latitude.
Related physics tools
Weight is the pull of gravity on a mass. Other gravity questions use the same law.
For the pull between any two masses, use the gravitational force calculator. The pendulum calculator shows how gravity sets a swing’s period.
Common mistakes
Mistake: Saying you weigh 70 kg on Mars.
Instead: Your mass is 70 kg everywhere; your weight is lower.
Mistake: Treating kilogram-force as kilograms.
Instead: 1 kgf is the weight of 1 kg in standard gravity, 9.80665 N.
Checking the method
A separate script re-works every golden value through pounds and pound-force, with the NASA gravity table, instead of newtons first.
Read how we test our calculators, or browse more maths calculators.