How big is Uranus compared to Mars?
Data as of July 2026
7.5×wider than Mars
Uranus is 7.5× wider than Mars: 50,724 km across against Mars’s 6,779 km. By volume, about 419 Marses would fit inside Uranus. Uranus has 136× Mars’s mass.
▶ See Uranus and Mars in 3D
Side by side
Diameter
Uranus 50,724 km · Mars 6,779 km
Width ratio
Uranus is 7.5× wider
Volume
419 Marses fit inside Uranus
Mass
Uranus is 136× Mars
Gravity (Uranus · Mars)
8.7 m/s² · 3.7 m/s²
Distance from Sun
19.2 AU · 1.52 AU
A year on Uranus lasts 84 Earth years, nearly 45 Mars years. Since Voyager 2 flew past in 1986, Uranus has not yet completed half of one orbit.
What sets them apart
Uranus is seven and a half times wider than Mars and around 135 times its mass. Mars is a small rocky desert under a thin atmosphere and the most visited planet after Earth; Uranus is an ice giant of water, ammonia and methane beneath hydrogen and helium, seen up close only once.
Ratios are easy to nod along to and impossible to picture. In the interactive view, switch to True scale to see Uranus 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 Found something out of date?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.