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Space & planets

How wide is the Moon?

The Moon is 3,475 km · 2,159.3 mi across.

Moon at true scale

  1. Moon 3,475 km · 2,159.3 mi
  2. Mars 6,792 km · 4,220.4 mi
  3. Earth 12,756 km · 7,926.2 mi

Moon (blue) beside Mars and Earth, all on one scale.

NASA’s planetary fact sheet gives the Moon a diameter of 3,475 km, about 27% of Earth’s 12,756 km. Pluto, at 2,376 km across, is smaller still.

Compared with familiar things

  • The Moon is about 51% of Mars (6,792 km · 4,220.4 mi).
  • The Moon is about 27% of Earth (12,756 km · 7,926.2 mi).

Can you guess it by eye?

Play five comparisons featuring the Moon: resize each object beside a fixed reference, then see how close you were. No sign-up needed.

Play five comparisons

What is measured

Diameter: 3,475 km · 2,159.3 mi. NASA NSSDC planetary fact sheet diameter of the Moon, 3,475 km.

Source: NASA Planetary Fact Sheet (NSSDC). Checked 2026-09-28. The silhouette is scaled so this measurement is exact; its other proportions are illustrative.