MasterTool

Escape Velocity Calculator

Calculate escape velocity instantly in your browser — the published formula, worked locally with no data sent anywhere.

NASA planetary masses and radii last updated · reference source

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Dated static reference; no live data is fetched. Verify current source values and assumptions before relying on results.

What this tool does

Calculate escape velocity instantly in your browser — the published formula, worked locally with no data sent anywhere. Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.

How to use the Escape Velocity Calculator

  1. Enter or select body.
  2. Enter or select altitude above the surface (km).
  3. Read the calculated result; change any measurement to compare alternatives.

Formula

escape velocity v = √(2GM/r) with G = 6.674×10⁻¹¹ — the speed at which kinetic energy exactly balances gravitational potential energy, using NASA factsheet masses and mean radii.
planet
Body
altKm
Altitude above the surface (km)

Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.

Worked example

For escape velocity calculator, the following measurements illustrate the exact method: Body: earth; Altitude above the surface (km): 0.

Inputs

  • BodyEarth
  • Altitude above the surface (km)0

Result

  • Escape velocity (km/s)11.19
  • Escape velocity (m/s)11,185.73
  • Escape velocity (mph)25,021.8
  • Orbital velocity at this radius (km/s)7.91

Results explained

Escape velocity (km/s)
Escape velocity (km/s) from the formula above. Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.
Escape velocity (m/s)
Escape velocity (m/s) from the formula above. Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.
Escape velocity (mph)
Escape velocity (mph) from the formula above. Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.
Orbital velocity at this radius (km/s)
Orbital velocity at this radius (km/s) from the formula above. Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.

Frequently asked questions

escape velocity v = √(2GM/r) with G = 6.674×10⁻¹¹ — the speed at which kinetic energy exactly balances gravitational potential energy, using NASA factsheet masses and mean radii.

Surface (or entered-altitude) escape speed for a non-rotating spherical body, ignoring atmosphere. Earth's 11.2 km/s is about 33 times the speed of sound at sea level; a rocket doesn't need to reach it in one burst because it keeps thrusting.

Every field is labelled with its unit — enter values in exactly the labelled unit and read the result in the labelled output unit. Fields with a unit symbol also support the site-wide imperial/metric switch, which converts before the formula runs.

It uses double-precision arithmetic and the published constants and formulas named on this page. The last displayed digit may be rounded, and real conditions can differ from the idealized model described in the assumptions.

Yes. Every calculation runs entirely in your browser; nothing you enter is uploaded, stored or shared.