How big is Uranus compared to Neptune?
≈ samealmost exactly Neptune’s size
Uranus is almost exactly the same width as Neptune — 50,724 km across against Neptune’s 49,244 km. By volume, the two have almost the same volume. Uranus has about 85% of Neptune’s mass.
▶ See Uranus and Neptune in 3D
Side by side
Diameter
Uranus 50,724 km · Neptune 49,244 km
Width ratio
about equal
Volume
almost equal
Mass
Uranus is 85% of Neptune
Gravity (Uranus · Neptune)
8.7 m/s² · 11.2 m/s²
Distance from Sun
19.2 AU · 30.1 AU
Uranus is the wider planet but the lighter one — a clean reminder that size and mass are not the same thing.
What sets them apart
These two ice giants are the solar system’s most easily confused pair, and for good reason: they are almost the same size. Uranus is very slightly wider, yet Neptune is the heavier of the two — about 18% more massive — because it is denser. Uranus is the coldest planet; Neptune has the strongest winds.
Ratios are easy to nod along to and impossible to picture. In the interactive view, switch to True scale to see Uranus and Neptune 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 Found something out of date?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.