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 Found something out of date?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.