The moon's mean radius is 1,079.6 miles (1,737.5 kilometers). Double those figures to get its diameter: 2,159.2 miles (3,475 km). The moon's equatorial circumference is 6,783.5 miles (10,917 km). The moon's surface area is about 14.6 million square miles (38 million square kilometers), which is less than the total surface area of the continent of Asia (17.2 million sq mi or 44.5 million sq km).