What is the circumference of the Earth? How far around is the Earth? The average radius of the Earth is 3,959 miles (6,374 kilometers). The equatorial diameter of the Earth (distance from one side of the Earth to the other at the equator) is about 7,926 miles. The ratio of the circumference to the diameter of a circle (circumference/diameter) is written as the symbol pi. Pi is approximately 3.141592. 3.14159265 3.1415926535 Therefore, to determine the circumference from the diameter given above: equatorial diameter x 3.141592 = equitorial circumference | | 7,926 x 3.141592 = 24,900 | | The earth has a circumference of approximately 24,900 miles. More precisely the circumference of the earth at the equator is 24,902 mi / 40,076 km. a North-South circumference, however (passing through both North and South Poles) is slightly less, as the Earth is not a sphere but an oblate spheroid, somewhat fattened in its North-South axis but the effect of rotation. The Earth's circumference is about 24,900 miles.