Calculates the minimum speed an object needs to completely escape a body’s gravitational pull, ignoring atmospheric drag.
How it works
The gravitational constant, the body’s mass, and its radius combine directly in the standard escape velocity formula.
What this does not include
This does not include atmospheric drag, which would require additional speed to overcome in a real launch — this calculator gives the idealized minimum in a vacuum.
How to use this calculator
- Enter the body’s mass and radius.
A worked example
Earth’s mass (5.972×10²⁴ kg) and radius (6.371×10⁶ m) give an escape velocity of 11,185.7265 m/s — about 11.2 km/s.
The Moon’s mass (7.342×10²² kg) and radius (1.737×10⁶ m) give a much lower 2,375.2831 m/s — roughly a fifth of Earth’s, which is why leaving the Moon takes so much less fuel.
What the variables mean
| Variable | Meaning |
|---|---|
| Mass | Mass of the body being escaped from, in kilograms |
| Radius | Radius of the body, in meters |
Edge cases worth knowing
Escape velocity depends on both mass and radius, not mass alone. A smaller, denser body can have a similar escape velocity to a larger, less dense one — it’s the mass-to-radius relationship that matters.
A radius of zero makes the result infinite, which has no physical meaning — the calculator declines to show a value in that case.
Frequently asked questions
Why is Earth’s escape velocity about 11.2 km/s?
It comes directly from Earth’s mass and radius plugged into the escape velocity formula — a well-known reference figure in spaceflight.
Why is the Moon’s escape velocity so much lower?
The Moon has far less mass and a smaller radius than Earth, both of which reduce the gravitational pull an object needs to overcome.
Does escape velocity depend on the object’s own mass?
No — the formula only depends on the mass and radius of the body being escaped, not the mass of the object trying to escape it.
