Satellite Orbital Speed Calculator
For a satellite in a circular orbit, the gravitational force provides the centripetal acceleration needed to maintain the orbit. Setting these equal gives the orbital speed as v = sqrt(GM/r), where r is the orbital radius (planet center to satellite). At higher altitudes, gravity is weaker, so satellites orbit more slowly and take longer to complete each lap. This calculator accepts altitude above the planet surface, adds the planet's mean radius to get the orbital radius, then computes orbital speed, orbital period, and escape velocity at that altitude.
Orbital speed formula
v = sqrt(GM / r) where r = R_body + altitude
T = 2π * r / v (orbital period)
v_escape = sqrt(2) * v (escape velocity at same r)
GM (standard gravitational parameter) from NASA: Earth = 3.986 x 10 to the 14th m cubed/s squared; Moon = 4.905 x 10 to the 12th; Mars = 4.283 x 10 to the 13th. Using GM directly avoids the separate uncertainties in G and M.
Key orbit altitudes for Earth
Low Earth Orbit (LEO): 160 to 2,000 km, v = 7,300 to 7,900 m/s, T = 88 to 127 minutes. Medium Earth Orbit (MEO): 2,000 to 35,786 km (GPS at 20,200 km, v = 3,874 m/s). Geostationary (GEO): 35,786 km, v = 3,075 m/s, T = 23h 56m (sidereal day). Lunar orbit: 384,400 km, v = 1,023 m/s.
Satellite orbital speed: frequently asked questions
What is the formula for satellite orbital speed?
For a circular orbit, the orbital speed is v = sqrt(GM / r), where G is Newton's gravitational constant, M is the central body's mass, and r is the orbital radius (center of planet to satellite). For Earth, using GM = 3.986 x 10 to the 14th m cubed/s squared, a 400 km altitude orbit gives v = sqrt(3.986e14 / 6,771,000) = 7,672 m/s (about 27,600 km/h).
How fast does the ISS orbit the Earth?
The International Space Station orbits at about 408 km altitude, giving an orbital radius of 6,778 km. Its orbital speed is approximately 7,667 m/s (27,600 km/h or 17,100 mph). It completes one orbit in about 92 minutes.
What is the escape velocity, and how does it relate to orbital speed?
Escape velocity at the same radius is sqrt(2) times the circular orbital speed. At Earth's surface, escape velocity is about 11,186 m/s (40,270 km/h). A satellite traveling at sqrt(2) * orbital speed at any altitude will escape Earth's gravity.
Why do higher orbits have lower speeds?
Orbital speed decreases as altitude increases because gravitational force decreases with distance (as 1/r squared). The orbital speed scales as 1/sqrt(r), so doubling the orbital radius decreases speed by a factor of sqrt(2).
What is geostationary orbit speed?
The geostationary orbit (GEO) is at 35,786 km altitude, giving an orbital radius of 42,164 km. The orbital speed is approximately 3,075 m/s (11,070 km/h). At this speed and altitude, the satellite completes one orbit in exactly 24 hours, staying fixed over the same point on Earth.
Official sources
- NASA Planetary Fact Sheets (GM and radii): nssdc.gsfc.nasa.gov/planetary/factsheet/.
- NASA Glenn Research Center orbital mechanics: grc.nasa.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.