Mercury has a radius of 1,516 miles, an equatorial circumference of 9,525.1 miles and a volume of 14.59 billion cubic miles. Based on radius, Mercury is 0.38 times the size of Earth and is the smallest planet in the solar system.
By comparing the equatorial circumference of Mercury to the equatorial circumference of Earth, Mercury is .00015 times the size of Earth. Compared by volume, Mercury is only 0.05 times the size of Earth. Mercury has a surface area of 28.87 million square miles, which gives it only 0.14 times of the surface area of Earth. The mass of Mercury is equal to about .3010 x 10^23 kilograms.