Earth vs Mars: size comparison
Earth: 12,742 km. Mars: 6,779 km. Both silhouettes are drawn at the same scale.
Size ratio: ×1.9
Earth
12,742 km
What is measured Mean diameter of the Earth
Earth's equator is about 40,075 km around.
Source : Wikipedia — Earth
Mars
6,779 km
What is measured Mean diameter of Mars
Mars has half Earth's diameter, yet as much dry land.
Source : Wikipedia — Mars