Earth has a mean radius of 3,959 miles. This value is an average, however, as the Earth is only approximately spherical, and the exact distance from its surface to its center varies with latitude and local topography.
Earth is an oblate spheroid that is somewhat flattened at the poles. As a result, the distance from the surface to the core is shorter at the poles than anywhere else. The planet's rotation causes a distinct bulge at the equator, and local features, such as mountains, further increase the radius. Across the entire surface, the Earth's radius ranges from 3,947 to 3,968 miles.