Why does my weight change on different planets if my mass stays the same?

Weight is a force: W = m*g. Mass m is an intrinsic property that does not change. But surface gravitational acceleration g varies — Jupiter's is about 2.5 times Earth's, so you would weigh 2.5 times more there.

What is the surface gravity of Mars compared to Earth?

Mars has a surface gravity of about 3.72 m/s^2, roughly 38% of Earth's 9.81 m/s^2. A person with a mass of 70 kg would weigh about 687 N on Earth but only about 260 N on Mars.

What does the Moon's surface gravity feel like?

The Moon's surface gravity is about 1.62 m/s^2, approximately 1/6 of Earth's. A 70 kg person would weigh only about 113 N there, allowing the bounding gait seen in Apollo astronaut footage.

Planetary Weight Calculator

Find your weight on any planet or moon by entering your mass and the surface gravitational acceleration. Uses W = m * g. Preset values for Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and the Moon are listed for reference.

By AbraCalc Editorial Team · Reviewed by AbraCalc Methodology Review · Last reviewed: 2026-06-25

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How to use this tool

Enter mass (m) and surface gravity (g) in the fields above.
Results update instantly as you type — or click Calculate.
Read your weight and the full breakdown beneath it.

Formula

W = m * g

How it works

Weight W is the gravitational force on a mass m at a surface where gravity is g. W = mg. On Earth g ≈ 9.81 m/s²; on Mars g ≈ 3.72 m/s²; on the Moon g ≈ 1.62 m/s².

Reference surface gravities (m/s²): Mercury 3.70, Venus 8.87, Earth 9.81, Moon 1.62, Mars 3.72, Jupiter 24.79, Saturn 10.44, Uranus 8.87, Neptune 11.15.

Worked examples

70 kg person on Mars

70 kg person on the Moon

Common mistakes to avoid

Confusing mass (kg) and weight (N) — mass is the same everywhere; weight W = m*g varies by planet because g differs.
Entering weight in newtons as if it were mass in kilograms — bathroom scales read in kg but are measuring gravitational force, so on another planet the scale reading would change even though your actual mass does not.
Using Earth's g (9.81 m/s^2) for all bodies instead of the specific surface gravity of the planet or moon of interest.

Key terms

Frequently asked questions

Why does my weight change on different planets if my mass stays the same?: Weight is a force: W = m*g. Mass m is an intrinsic property that does not change. But surface gravitational acceleration g varies — Jupiter's is about 2.5 times Earth's, so you would weigh 2.5 times more there.
What is the surface gravity of Mars compared to Earth?: Mars has a surface gravity of about 3.72 m/s^2, roughly 38% of Earth's 9.81 m/s^2. A person with a mass of 70 kg would weigh about 687 N on Earth but only about 260 N on Mars.
What does the Moon's surface gravity feel like?: The Moon's surface gravity is about 1.62 m/s^2, approximately 1/6 of Earth's. A 70 kg person would weigh only about 113 N there, allowing the bounding gait seen in Apollo astronaut footage.