Escape Velocity Calculator

v_e = √(2GM/r). Speed needed to escape gravitational pull of body.

Inputs

Result

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General calculation reads

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How to use this calculator

  • Pick a body (or Custom + M, r).
  • Read v_e in km/s and mph.

About this calculator

Escape velocity is the minimum speed needed to break free from a body's gravity (with no further propulsion). Derived from energy conservation: ½mv² = GMm/r. Earth: 11.2 km/s. Moon: 2.4 km/s. Sun (from surface): 617 km/s. Jupiter: 59.5 km/s. Black hole event horizon: c (speed of light, by definition). Note v_e is independent of escaping object's mass — same speed for atom or rocket.

Frequently asked

Independent of mass?+
Yes — gravity force scales with mass; required KE also scales with mass. Cancels out.
Why is Sun's v_e so high?+
Massive (1.989e30 kg) vs. surface radius. Most of mass is "below you" — strong gravity.
Black hole?+
v_e at event horizon = c. Beyond that, nothing escapes — the defining property.
Real rocket needs more?+
Yes — gravity losses + atmosphere + thrust profile. SLS to Earth-escape needs 12+ km/s effective Δv vs. 11.2 km/s pure escape.
Escape from solar system?+
From Earth's orbit: 16.6 km/s heliocentric, but Earth gives ~30 km/s for free. Only need ~12 km/s extra from Earth's frame.

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