Calculators
Escape Velocity Calculator
Calculate Newtonian escape speed from central body mass and distance from its centre in SI units.
Enter the central body mass in kilograms and your distance from its centre in metres. Scientific notation such as 5.972e24 is accepted. This Newtonian model assumes an isolated spherical body, ignores atmosphere and rotation, and calculates the initial speed needed to escape without further thrust. Calculations run locally in your browser.
Calculate escape speed with v = √(2GM/r).
Enter mass in kilograms and distance from the centre in metres, not altitude above the surface. For altitude h above a body of radius R, enter r = R + h. Using 5.972e24 kg and 6371000 m gives approximately 11186 m/s, or 11.186 km/s. The model assumes an isolated spherical body and ignores atmosphere, rotation, other bodies, and relativistic effects. The escaping object is assumed to have negligible mass. Results are educational estimates; all calculations stay in your browser.
Frequently Asked Questions
Everything you need to know about this tool, how it works, and privacy.
What formula calculates escape velocity?
The calculator uses v = sqrt(2GM/r), where G = 6.67430e-11 m³/(kg·s²), M is central body mass in kilograms, and r is distance from its centre in metres. Earth-like inputs of 5.972e24 kg and 6371000 m give about 11.186 km/s.
Should I enter radius or altitude?
Enter distance from the centre. At the surface this is the body radius. At an altitude h above the surface, add the radius and altitude first; both must be in metres.
What inputs are accepted?
Both values must be positive finite numbers between 1e-20 and 1e40 inclusive. Scientific notation is accepted, allowing planetary and stellar masses. Zero, negative, missing, and out-of-range values show an error.
What are the limitations?
This is a Newtonian estimate for an isolated spherical body with a negligible-mass escaping object. It ignores atmosphere, rotation, other bodies, and relativity. Near compact objects, a relativistic model is needed. Escape speed is an initial speed without further propulsion, not a rocket fuel estimate.
Are my inputs uploaded?
No. Calculation and copying run locally in your browser.