Escape Velocity Calculator
Find the minimum speed needed to escape a planet or moon's gravity completely, and see how it compares across the solar system.
Calculator verified • Last updated: August 2026
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Escape Velocity Across the Solar System
Mass and size both matterEscape velocity grows with a body's mass but shrinks with its radius, so it's not simply proportional to how "big" a planet feels. Jupiter's enormous mass gives it by far the highest escape velocity here, while the Moon's low mass makes it comparatively easy to leave.
Escape Velocity Explained
Escape velocity is the minimum speed an object needs to break free of a planet or moon's gravity permanently, without any further propulsion, assuming no atmospheric drag.
v: escape velocity, in meters per second (m/s).
G: the gravitational constant, about 6.674 × 10⁻¹¹ N·m²/kg².
M: mass of the body being escaped, in kilograms (kg).
r: distance from the center of the body (usually its surface radius), in meters (m).
This comes directly from setting kinetic energy equal to gravitational potential energy — the exact speed at which an object has just enough energy to reach infinite distance with zero velocity remaining.
Worked Example: Leaving Earth
Using the calculator's defaults — Earth's mass ( kg) and radius (6,371,000 m) — escape velocity works out to about 11.2 km/s, or roughly 40,270 km/h. That's the speed real spacecraft must reach (with the help of multi-stage rockets) to leave Earth's gravity entirely, rather than just reaching orbit, which requires a much lower orbital velocity of about 7.8 km/s.
Escape Velocity vs. Orbital Velocity
These are often confused but describe different things: orbital velocity is the speed needed to continuously fall around a planet without escaping (staying in a stable orbit), while escape velocity is the speed needed to leave entirely. Escape velocity is always exactly times the circular orbital velocity at the same distance — which is why reaching orbit takes noticeably less energy than escaping a planet's gravity altogether.
A Brief History of Escape Velocity
The concept follows directly from Newton's law of universal gravitation (1687), though it wasn't of much practical interest until the dawn of the space age. Konstantin Tsiolkovsky's early 20th-century rocket equation work laid the theoretical groundwork for calculating what it would actually take to reach escape velocity, decades before Sputnik's 1957 launch made the concept a practical engineering reality rather than a theoretical curiosity.
Common Escape Velocity Mistakes
Assuming escape velocity is needed to reach orbit is a common misconception — actual orbital speed is significantly lower, and confusing the two overestimates the energy needed for a satellite launch. Forgetting that escape velocity depends on the starting distance , not just the planet, is another frequent slip — escape velocity from a high orbit is lower than from the surface, since is larger. Ignoring atmospheric drag when comparing real launch speeds to the theoretical escape velocity is a third common oversight, since it's calculated for idealized airless conditions.
Escape Velocity Terms You Should Know
Escape Velocity — the minimum speed to break free of a gravitational field with no further propulsion.
Orbital Velocity — the speed needed to maintain a stable circular orbit, lower than escape velocity by a factor of √2.
Gravitational Potential Energy — the stored energy an object has due to its position in a gravitational field.
Event Horizon — the boundary around a black hole where escape velocity equals the speed of light.
This formula assumes no atmospheric drag and a non-rotating spherical body; real launches account for both factors separately.
Frequently Asked Questions
Why is there an escape velocity instead of just needing constant thrust?
Escape velocity is the speed needed if an object coasts freely after a single push, with no further propulsion — a rocket with continuous thrust can technically escape at any speed, even very slowly, since it keeps adding energy along the way. Escape velocity specifically describes the one-time speed needed to have enough kinetic energy to overcome gravity's pull entirely on your own, coasting the rest of the way.
Does escape velocity depend on the direction you launch?
No — in the idealized case of a single point mass with no atmosphere, escape velocity only depends on speed, not direction, because it comes purely from an energy balance. In practice, launching in the direction a planet already rotates gives a free velocity boost from that rotation, which is why real rocket launches favor eastward trajectories from sites near the equator.
Why can't light escape a black hole if nothing can go faster than light?
A black hole's escape velocity, calculated with this same formula, exceeds the speed of light within its event horizon — since nothing can travel faster than light, nothing inside that boundary can ever escape, light included. This is precisely how the Schwarzschild radius is defined: the distance at which escape velocity equals the speed of light.