What is the diameter of the moon?

The diameter of the moon is approximately 3,474 kilometers or 2,159 miles. This makes the moon about one-quarter of the size of Earth.

Earth's moon is its only natural satellite and the fifth largest moon in the solar system. It spins slowly on its axis, completing 1 day in 27.3 Earth days. The moon's diameter from side to side is wider than its diameter from pole to pole. To put the moon's diameter in perspective, the diameter of the Earth is 7,917.5 miles, and the diameter of the Sun is approximately 865,000 miles. The Sun is the largest object in the solar system.