Escape Velocity Calculator
Calculate the escape velocity from a planet or moon given its mass and radius.
How it works
v = √(2 · G · M / r)
Escape velocity is the minimum speed an object needs to break free of a body's gravity without further propulsion. It depends only on the body's mass and radius, not on the escaping object's mass. G is the gravitational constant, 6.674 × 10⁻¹¹ N·m²/kg².
Worked example
For Earth (M ≈ 5.972 × 10²⁴ kg, r ≈ 6.371 × 10⁶ m): v = √(2 × 6.674e-11 × 5.972e24 ÷ 6.371e6) ≈ 11,186 m/s, about 11.2 km/s.
Frequently asked questions
Does escape velocity depend on the rocket's mass?
No. The mass of the escaping object cancels out, so a pebble and a spacecraft need the same speed. What differs is the energy required to reach that speed.
Why is Earth's escape velocity 11.2 km/s?
Plugging Earth's mass and radius into v = √(2GM/r) yields about 11,186 m/s. Larger or denser bodies have higher escape velocities.
Is this the speed to orbit?
No. Orbital velocity is lower — about 7.9 km/s for a low Earth orbit. Escape velocity is √2 times the circular orbital velocity at the same radius.
Related calculators
Educational estimate. Check the formula and units for your exact case.