Mercury's diameter is 3,030 miles (4,878 km), comparable to the size of the continental United States. This makes it about two-fifths the size of Earth. It is smaller than Jupiter's moon Ganymede and Saturn's moon Titan. read more
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. read more