How big is Venus compared to Mars?
1.8×wider than Mars
Venus is 1.8× wider than Mars — 12,104 km across against Mars’s 6,779 km. By volume, about 6 Marses would fit inside Venus. Venus has 7.6× Mars’s mass.
▶ See Venus and Mars in 3D
Side by side
Diameter
Venus 12,104 km · Mars 6,779 km
Width ratio
Venus is 1.8× wider
Volume
6 Marses fit inside Venus
Mass
Venus is 7.6× Mars
Gravity (Venus · Mars)
8.9 m/s² · 3.7 m/s²
Distance from Sun
0.72 AU · 1.52 AU
Venus and Mars sit on either side of Earth — one too hot, one too cold — which makes Earth’s temperate middle ground look less like a rule and more like luck.
What sets them apart
Earth’s two nearest neighbours, and its two most-compared cousins. Venus is nearly Earth-sized; Mars is about half Earth’s width and a fraction of its mass. Their fates diverged completely — Venus ran away into a 464 °C greenhouse, while Mars froze into a thin-aired desert.
Ratios are easy to nod along to and impossible to picture. In the interactive view, switch to True scale to see Venus and Mars at their honest relative sizes.
Keep going
✓ Facts verified July 2026
Every figure on this page is a real, rounded value checked against primary sources. Found something out of date? See how we keep it accurate.