Escape velocity calculator

What escape velocity actually means

Escape velocity is the minimum speed you need at a given altitude to break gravity's grip and never fall back — assuming no further thrust and no atmosphere. It is a function of the central body's mass and the distance from its center: v = √(2GM/r). The direction does not matter (in vacuum), only the speed.

Why rockets don't actually reach escape velocity at launch

The Saturn V did not leave the pad at 11.2 km/s. Rockets accelerate gradually because the engines keep firing during ascent. Escape velocity is the speed needed if you were given a single, instantaneous push. The Apollo spacecraft reached translunar injection at about 10.8 km/s after a long burn in low Earth orbit.

How black holes change the formula

Set v = c (speed of light) in the escape velocity equation, solve for r, and you get the Schwarzschild radius: r = 2GM/c². That is the event horizon — the surface below which the escape velocity exceeds light itself.