Universe Today offers a few fascinating ways to consider the size of the moon:
“The volume of the Moon is 2.195 x 1010 km3 [almost 22 billion km3]. That sounds like a huge number, but it’s actually only 2% the volume of the Earth. In other words, you could fit 50 moons inside the volume of the Earth.
The surface area of the Moon is 37.9 million square kilometers [3.79 x 1007, or almost 38 million square miles]. How big is that? Just for comparison, the surface area of Asia is 44.4 million kilometers. If you could unwrap the Moon, it wouldn’t quite fit inside Asia.
The mass of the Moon is 7.347 x 1022 kg. Once again, that sounds like a big number, but the mass of the Moon is only 1.2% the mass of the Earth. If you had a great big scale, and put the Earth on one side, you’d need a pile of moons stacked 81 high to match the mass of the Earth.
So now you know the size of the Moon.”