Surface Gravity Calculator
Compute the surface gravity of any body: g = GM/r². Companion to the escape-velocity calculator. Solve for g, mass, or radius. NASA / IAU body data populated automatically.
Limitations: Assumes a non-rotating, spherically-symmetric body. Real surface gravity varies with latitude (rotation flattens the body) and altitude (inverse-square falloff above the reference radius).
What to do next: Pick a body for fast lookup. The "Earth = 1 g" output makes alien-gravity comparisons intuitive — e.g., the Moon at 0.166 g means a 200 lb astronaut weighs 33 lbs there.