🌍 Orbital Velocity Calculator
Find the speed an object needs to maintain a stable circular orbit around a central body.
What sets orbital velocity
For a stable circular orbit, gravity provides exactly the centripetal force needed to keep an object moving in a circle. Setting these equal and solving gives the orbital velocity formula: v = √(GM / r), where G is the gravitational constant, M is the mass of the central body, and r is the orbital radius from the center of that body.
How this calculator works
Enter the mass of the central body being orbited and the orbital radius. The calculator applies the circular orbit velocity formula and reports the result in kilometers per second, meters per second, and kilometers per hour.
This is the speed needed for a perfectly circular orbit at that specific radius — going faster without changing radius would produce an elliptical or escape trajectory instead. This calculator is for general astronomy education and planning purposes.