Mercury vs Venus: size comparison
Mercury: 4,879 km. Venus: 12,104 km. Both silhouettes are drawn at the same scale.
Size ratio: ×2.5
Mercury
4,879 km
What is measured Diameter of Mercury
Mercury is barely larger than the Moon.
Source : Wikipedia — Mercury (planet)
Venus
12,104 km
What is measured Diameter of Venus
It is nearly Earth's twin in size, at 12,104 km across.
Source : Wikipedia — Venus