Why does Mars have lower gravity than Earth?

Mars has about 11% of Earth's mass and 53% of its radius, giving about 38% of Earth's surface gravity.

Does this formula work above the surface?

Yes, replace r with the distance from the centre (body radius + altitude). Gravity decreases as 1/r².

Standard gravity is defined as exactly 9.80665 m/s².

Compute the surface gravitational acceleration of a celestial body from its mass and radius using g = G M / r^2.

Body Mass

Body Radius

Surface Gravity

9.8195 m/s²

In Earth g1.0013 g

Surface Gravity vs Body Mass

g = G M / r²

*G* = 6.674e-11 N m² kg⁻²

*M* = body mass

*r* = body radius

Divide by 9.80665 m/s² to express in multiples of Earth's standard gravity.

Confirm Earth's surface gravity.

Calculate the speed needed to leave a gravitational field.

Find your weight on another world.

See how much you weigh on different planets.