Treated as a sphere, determining Earth's circumference would be its single most important measurement[2] (Earth actually deviates from a sphere by about 0.3% as characterized by flattening). The exact distance around the equator is 40,075.017 km [ 24,901.461 mi ][3] and around the poles is 40,007.863 km [ 24,859.734 mi ].[4]