Surface Gravity Calculator

Surface gravity is the acceleration a dropped object feels standing on a body, and it depends on both how much mass the body has and how tightly that mass is packed into its radius. The formula is the gravitational constant times the mass divided by the radius squared. Earth value is nine point eight one meters per second squared, the familiar g. This calculator returns the surface gravity in meters per second squared and as a multiple of Earth gravity, so you instantly see whether you would feel light or crushed. It reports mass and radius separately, unlike a simple weight lookup, so you can model any world you invent. Preset buttons load real bodies. It all runs in your browser.