How big is the moon? July 25, 2020September 25, 2011 by Pamela Landy The moon’s diameter is 2,160 miles. The earth’s diameter at the equator is 7,926.68 miles. Related Answers Is the moon ever actually blue? What are the names of the first astronauts who went to the moon? How old is the moon? Who did CBS’s news commentary on July 20, 1969, the day of the first moon landing? How many couples were married in the first mass wedding performed by the Rev. Sun Myung Moon? What artist’s life is the basis for W. Somerset Maugham’s novel The Moon and Sixpence (1919)?