How much bigger is the planet Mercury than our moon?

From " http://btc.montana.edu/messenger/elusive_planet/fastfact_5.php"

Mercury is the second smallest planet; only Pluto is smaller. Mercury’s diameter is 4879 km, while Earth’s is 12,756 km. In fact, Mercury is not much larger than our Moon, which has a diameter of 3475 km.

Mercury's mass is 4.6 times that of the moon. Mercury's mass is 3.3x10^23 kg, and the moon's is 7.35x10^22 kg. In terms of radius, Mercury is 2,440 km and the moon is 1,737. That is only 1.4 times larger.

https://en.wikipedia.org/wiki/Mercury_(planet)
https://en.wikipedia.org/wiki/Moon

Mercury's volume is approimately 60.8 billion cubic kilometers, while our moon's volume is 21.96 billion cubic kilometers. This means Mercury is about 2.76 times as large as the moon. Volume is only one way to measure size, but I think it works best in this case.

https://www.space.com/18647-how-big-is-mercury.html
https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html

You are right, barnhill23. Looking at a balloon and a cricket ball, one would say the balloon is bigger even though the cricket ball is more massive.

Using the figures given by ArlingtonVA, the ratio of the radii is 2440km/1737km or 1.405.

Raising this to the third power (volume is proportional to the cube of the radius) shows Mercury to be 2.772 times bigger than the Moon, in agreement with your approximate figure.