Escape Velocity Calculator
Calculate the escape velocity from a planet or moon's mass and radius.
Assumptions used in this calculation
- No atmospheric drag: Calculates the idealized escape velocity from gravity alone, ignoring atmospheric drag during ascent.
About this calculator
Launching anything off a planet or moon permanently, a rocket, a probe, requires reaching a minimum speed where kinetic energy overcomes the pull of gravity entirely, and that threshold speed depends on the celestial body's mass and radius in a way that isn't intuitive across wildly different bodies, from the Moon to a black hole. This calculator computes escape velocity, the minimum speed needed to break free of a body's gravity with no further propulsion, using v = √(2GM ÷ r), where G is the gravitational constant (6.6743 × 10⁻¹¹ N·m²/kg²), M is the central body's mass, and r is its radius. Enter a body's mass and radius and it returns escape velocity directly, without you needing to look up G or handle the square root by hand. Notably, escape velocity doesn't depend on the escaping object's own mass, a feather and a spacecraft need to reach the same speed to leave Earth's gravity, only the energy required to get each one there differs. This is an idealized calculation that ignores atmospheric drag during ascent.
Worked example
Earth
Result: 11.19 km/s
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