Planet Escape Speed Calculator
Calculate escape velocity from a planet.
About Planet Escape Speed Calculator
Escape velocity for Planet Escape Speed is the speed at which kinetic energy balances the gravitational potential energy holding an object on the surface. A smaller planet with weak gravity needs a much lower escape speed, which is why escaping a small moon is easy.
Formula
Planet Escape Speed
ve = sqrt(2GM/R)
- escape velocity
- The speed needed to break free of a body's gravity with no further thrust
Worked example
With the default values below, Planet Escape Speed Calculator returns Escape Velocity of 11,158.5. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Planet massminimum 0 kg
- 5,970,000,000,000,000,000,000,000 kg
- Planet radiusminimum 0 m
- 6,400,000 m
- Surface gravityminimum 0 m/s^2
- 9.81 m/s^2
Results
- Escape Velocity
- 11,158.5 m/s
- Escape Velocity
- 11.16 km/s
- Approximate Mach
- 32.5
Step by step
- 1Values used
- 2Planet Escape Speed
- 3Escape Velocity= 11,158.5 m/s
- 4Escape Velocity= 11.16 km/s
- 5Approximate Mach= 32.5
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Planet Escape Speed calculated?
ve = sqrt(2GM/R) Escape velocity for Planet Escape Speed is the speed at which kinetic energy balances the gravitational potential energy holding an object on the surface.
Why does Planet Escape Speed matter?
A smaller planet with weak gravity needs a much lower escape speed, which is why escaping a small moon is easy.
What values do I need to enter?
This calculator takes 3 inputs: Planet mass, Planet radius, Surface gravity. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.