How big is the Moon compared to Earth?
Side by side
An unusually large moon
At about a quarter of Earth’s width, the Moon is enormous relative to its planet: no other planet in the solar system has a moon so large compared to itself. That outsized size is a clue to its violent origin: the leading theory is that the Moon condensed from debris blasted into orbit when a Mars-sized world struck the young Earth. It is big enough, and close enough, to raise our ocean tides and to hold Earth’s tilt, and its seasons, steady.
Numbers only get you so far. In the interactive view, watch the Moon circle Earth at its true relative size, then switch to 1:1 scale to see how even our nearest neighbour becomes a speck across 384,400 km of empty space.
Keep going
Every figure on this page is a real, rounded value checked against primary sources. Found something out of date? See how we keep it accurate.