Escape Velocity Calculator

This calculator finds the escape velocity of a planet, moon or star, the minimum speed an object needs to break free from its gravity and never fall back, from the body's mass and radius. Escape velocity is one of the defining numbers of any astronomical body. Throw a ball upward and it returns, because it is too slow to escape Earth's pull; throw it fast enough, and it would keep going forever. That threshold speed is the escape velocity, and it depends only on the mass of the body and the distance from its centre, not on the mass of the escaping object, so a pebble and a spacecraft need the same speed. It rises with mass and falls with radius, which is why escaping a massive, compact body is so much harder. For Earth, escape velocity is about 11.2 kilometres per second, roughly 40,000 kilometres per hour, which is why launching to deep space demands such powerful rockets. This tool computes it for any body. You enter the mass in kilograms and the radius in metres, with scientific notation supported for these large values, and the calculator returns the escape velocity in metres per second and kilometres per second. The results update as you type, so you can compare different planets or see how compactness raises the figure. Use it for physics and astronomy homework, for understanding space travel, or out of curiosity about other worlds. Taken to its extreme, when a body is so massive and compact that its escape velocity would exceed the speed of light, not even light can escape: that is a black hole. The same simple formula points the way to one of the most exotic objects in the universe.

Escape velocity = square root of (2 x G x mass / radius), with G = 6.674 x 10^-11. It does not depend on the escaping object's mass. Scientific notation supported.