How Big Is Earth?

Earth has a diameter at the Equator of about 12,756 kilometers (7,926 miles), making it the fifth largest planet in the solar system. Earth’s mass is about 5.97 ⨉ 10²⁴ kilograms. Dividing this mass by Earth’s volume results in an average density of approximately 5,517 kilograms per cubic meter. This density reflects the composition of Earth’s interior, which is composed of elements like iron and nickel.

While often referred to as a sphere, Earth is actually an oblate spheroid, meaning it is slightly flattened at the poles and bulging at the Equator. Earth’s surface area is about 510 million square kilometers (197 million square miles). The surface is divided into land and water, with about 71 percent covered by oceans.