Mars vs Moon: size comparison
Mars: 6,779 km. Moon: 3,475 km. Both silhouettes are drawn at the same scale.
Size ratio: ×2
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
Moon
3,475 km
What is measured Mean diameter of the Moon
It drifts away from Earth by about 3.8 cm a year.
Source : Wikipedia — Moon