Question: How big is Mars?
Solution: Mars is about half the size of Earth, with a diameter of approximately 6,779 kilometers (4,212 miles). This makes it the second smallest planet in the solar system, larger only than Mercury.
In terms of surface area, Mars has about 144.8 million square kilometers (55.9 million square miles), which is roughly equivalent to the total land area of Earth. Despite its smaller size, Mars has the tallest volcano and the largest canyon in the solar system: Olympus Mons and Valles Marineris, respectively.