# How Fast Can the Earth Rotate?

The Earth has an equatorial speed of **465.1 m/s, 1,674.4 km/h or 1,040.4 mi/h**.

Some sources state that Earth’s equatorial speed is slightly less, or 1,669.8 km/h. This is obtained by dividing Earth’s equatorial circumference by 24 hours. However, the use of only one circumference unwittingly implies only one rotation in inertial space, so the corresponding time unit must be a sidereal hour. This is confirmed by multiplying by the number of sidereal days in one mean solar day, 1.002 737 909 350 795, which yields the equatorial speed in mean solar hours given above of 1,674.4 km/h.

The tangential speed of Earth’s rotation at a point on Earth can be approximated by multiplying the speed at the equator by the cosine of the latitude.

For example, the Kennedy Space Center is located at 28.59° North latitude, which yields a speed of: 1,674.4 kilometres per hour (1,040.4 mph) × cos (28.59) = 1,470.23 kilometres per hour (913.56 mph)