Orbital Velocity Calculator

Your details

Choose a preset body or "Custom" to enter your own central mass and surface radius.
A circular orbit holds one speed; an elliptical orbit speeds up near the body and slows at its far point.
Altitude is measured from the surface; radius is measured from the centre of the body.
Height of the orbit above the surface. 0 km is a surface-skimming low orbit; the ISS is about 420 km.
Only used to report total orbital energy. It does not change the speed, which is mass independent.
kg
Orbital velocityPlanetary low-orbit speed
7,909.5m/s
In km/s7.91 km/s
Orbital period1h 24min
Escape velocity (at this radius)11,185.7m/s
Centripetal acceleration9.8195m/s²
Orbital velocity7,909.5
Escape velocity11,185.7

A stable circular orbit requires 7.91 km/s (7,910 m/s).

  • Orbital velocity depends only on the central mass and the radius; the orbiting object’s own mass cancels out of the equation.
  • Move to a higher orbit and the required speed falls; a lower orbit demands a faster speed.
  • Escape velocity from this radius is √2 times higher, about 11.186 km/s.

Next stepCompare this against escape velocity to see how much extra speed it takes to leave the orbit entirely.

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