Earth Orbit Calculator
Find orbital speed and period at a given altitude above Earth.
Find how fast a satellite must travel and how long its orbit takes.
The math behind it
Circular orbit speed v = √(GM/r) and period T = 2π√(r³/GM), where r is measured from Earth's center.
Worked example
400 km (ISS altitude) → about 7672 m/s, 92.6 min period.
FAQ
Why do higher orbits move slower?
Weaker gravity needs less speed to stay in orbit.