Escape Velocity Calculator

Escape velocity is exactly √2 times orbital velocity at the same radius — always, for every body, with no dependence on mass or size. Getting into orbit is most of the work; leaving entirely costs only 41% more speed. The mass of what is escaping never appears. A pebble and a rocket need the same 11.2 km/s from Earth's surface, which is the same reason everything falls at the same rate. Escape velocity assumes a single unpowered impulse and no atmosphere, so it is not a rocket's required speed — a rocket accelerates continuously and never needs to reach it all at once. The Schwarzschild radius is this calculation carried to its limit: compress the mass inside that radius and escape velocity would exceed the speed of light. For Earth it is under a centimetre.