Planetary Surface Gravity Calculator

Surface gravity is the gravitational acceleration at the surface of a planetary body.

Formula:

g = GM / R²

Where:

• G = 6.674 × 10⁻¹¹ N·m²/kg²
• M = mass of the body (kg)
• R = radius of the body (m)

Surface gravity around the Solar System:

Which radius the gas giants use, and why it matters: The four giant planets have no surface to stand on, so “surface gravity” is quoted at the altitude where the atmospheric pressure reaches one bar, using the equatorial radius. That convention is worth stating because these planets are visibly squashed by their own rotation. Jupiter’s equatorial radius is 71,492 km while its polar radius is only 66,854 km, a 7% difference, and gravity goes as 1/r². Feed the mean volumetric radius into the formula instead and you get 25.9 m/s² for Jupiter rather than 24.79, which is where a lot of the disagreement between published tables comes from. You will also see Uranus listed as 8.69 in some references; that figure comes from a different radius convention. This page uses the equatorial 1-bar values throughout, so the table, the calculator and the chart all agree.

Note the coincidence in the table: Venus and Uranus have almost exactly the same surface gravity, despite Uranus being fifteen times more massive. Uranus is simply so much larger and less dense that the two cancel out.

Weight calculation: Weight = mass × g

On Mars, a 70 kg person would weigh only 26 kg-equivalent, and could jump nearly 3× higher. On Jupiter’s cloud tops, they would weigh 177 kg-equivalent and could barely stand.

Note on “weight on other planets”: The mass of a person (in kg) never changes — only their weight (in Newtons) changes. We convert back to “kg-equivalent” by dividing the force by Earth’s gravity (9.81 m/s²) for easy intuitive comparison.