What is the size of the moon?

The moon has a diameter of 3474.8 kilometers. The moon is 27 percent the size of Earth but has only 1.2 percent of the Earth's mass.

A Greek astronomer and mathematician named Aristarchus of Samos, who lived over 2,300 years ago, first proposed the question of the size of the moon. After studying the moon and the shadows the Earth cast on it, Aristarchus estimated the size of the Earth to be 2 2/3, or 2.67, times larger than the moon. However, after additional scientific study, we now know that the Earth is actually 3.7 times larger than the moon. The moon also has a gravitational pull that is 17 percent that of Earth's.