By Amanda Rumble – Updated March 24, 2022
Image: tetmc/iStock/GettyImages
Weight reflects the gravitational pull of the planet you stand on. If you step onto a different celestial body, your weight changes because gravity differs. The Moon exerts roughly one‑sixth the pull of Earth, so you would weigh considerably less.
Gravitational force depends on an object's mass and your distance from its center. When you’re on a planet’s surface, that distance is simply the planet’s radius.
Comparing the Moon to Earth: the Moon’s mass is 0.0123 × Earth’s, and its radius is 0.273 × Earth’s. To determine the Moon’s gravity relative to Earth’s, divide the mass ratio by the square of the radius ratio:
g_{Moon}/g_{Earth} = 0.0123 / 0.273² ≈ 0.165
Record your weight in pounds or kilograms. For example, suppose you weigh 135 lb.
Multiply your Earth weight by 0.165, the Moon’s gravity relative to Earth.
For a 135 lb Earth weight, the calculation is 135 lb × 0.165 ≈ 22.28 lb. Your mass remains unchanged; only the weight you feel changes.
Knowing this simple formula lets you estimate your lunar weight anytime, whether you’re planning a space-themed event or just curious.
