Earth is classified as the largest of the terrestrial planets based on its circumference and diameter as well. At the equator, Earth's circumference is 24,901.55 miles (40,075.16 km). It is slightly smaller between the North and South poles at 24,859.82 miles (40,008 km).Earth's diameter at the poles is 7,899.80 miles (12,713.5 km) while it is 7,926.28 miles (12,756.1 km) at the equator. For comparison, the largest planet in Earth's solar system, Jupiter, has a diameter of 88,846 miles (142,984 km).arth's Size. As the largest of the terrestrial planets, Earth has an estimated mass of 5.9736 × 10 24 kg. Its volume is also the largest of these planets at 108.321 × 10 10 km 3. In addition, Earth is the densest of the terrestrial planets as it is made up of a crust, mantle and core.