What this calculator does
Your mass is the same everywhere in the universe; your weight is not. Weight is the force gravity exerts, so it changes with whichever body you are standing on while the amount of matter in you stays identical.
The differences are large. On the Moon a 70 kilogram person weighs about a sixth of their Earth weight, which is why the Apollo astronauts could bound about in bulky suits. On Jupiter the same person would weigh over two and a half times more.
The formula
Multiply your mass by the surface gravity of the chosen body. Dividing that weight by Earth gravity gives the Earth-equivalent mass, which is the figure that conveys how heavy you would feel.
| Term | Meaning |
|---|---|
| Mass | The amount of matter in an object, in kilograms. Identical everywhere. |
| Weight | The gravitational force on that mass, in newtons. Depends entirely on where you are. |
| Surface gravity | The gravitational acceleration at a body's surface, which depends on both its mass and its radius. |
The inputs explained
| Field | What to enter |
|---|---|
| Your mass (kg) | Your mass in kilograms, which is what bathroom scales display. |
| Body | The body to calculate for. Each has its own surface gravity. |
When to use it
Understanding the Apollo footage
Lunar gravity is about a sixth of Earth's, which explains the loping gait astronauts adopted.
Appreciating why Mars is a plausible destination
Martian gravity is roughly a third of Earth's, which is far more manageable than the Moon for long stays.
Separating mass from weight
Seeing the same mass produce wildly different weights makes the distinction concrete rather than a definition to memorise.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
What would 70 kg weigh around the solar system?
The same mass on a range of bodies.
| Body | Weight on that body | Feels like (Earth-equivalent mass) |
|---|---|---|
| Moon | 113.40 N | 11.56 kg |
| Mars | 259.70 N | 26.47 kg |
| Earth | 686.70 N | 70.00 kg |
| Jupiter | 1,735.30 N | 176.89 kg |
Questions
Would I actually be lighter, or just feel lighter?
Genuinely lighter in the technical sense, because weight is a force and that force really is smaller. Your mass, and therefore the amount of you, is completely unchanged.
Why is Jupiter's gravity not far stronger, given its size?
Because surface gravity depends on mass divided by radius squared, and Jupiter is enormously wide as well as massive. The radius partly cancels the mass, leaving surface gravity only about 2.5 times Earth's.
Could you stand on Jupiter at all?
No, it has no solid surface. The figure refers to gravity at the cloud tops, which is a reference level rather than somewhere you could stand.
Why do bathroom scales read kilograms?
They measure the force you exert and divide by Earth gravity to display a mass. Taken to the Moon and left uncalibrated they would show about a sixth of your real mass.
For the force and gravity relationship generally, see the force, mass and acceleration calculator. For the gravitational attraction between two bodies, see the Newton's law of gravitation calculator.