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Escape Velocity Calculator

Compute the escape velocity from any astronomical body, or solve for the body's mass or radius from a known escape velocity. Default body data comes from NASA fact sheets (Earth, Moon, Mars, Sun); supports custom bodies via mass + radius.

Solve for

Astronomical body

Custom mass (kg, optional)

Custom radius (m, optional)

Escape velocity (m/s, when solving for mass or radius)

Limitations: Assumes a non-rotating, spherically-symmetric body and ignores atmospheric drag. Real launch energy is HIGHER because of atmospheric resistance and gravity-loss during ascent. Does not model orbital launches — for orbital insertion, the relevant target is orbital velocity, which is √(GM/r) at the orbital radius.

What to do next: Pick a body for fast lookup, or leave the body blank and fill custom mass + radius for hypothetical bodies (exoplanets, asteroids, stars). The result warnings include the source citation for every looked-up value plus a cross-check against the body's published escape velocity.