How big is Jupiter compared to Neptune?
2.8×wider than Neptune
Jupiter is 2.8× wider than Neptune — 139,820 km across against Neptune’s 49,244 km. By volume, about 23 Neptunes would fit inside Jupiter. Jupiter has 18.6× Neptune’s mass.
▶ See Jupiter and Neptune in 3D
Side by side
Diameter
Jupiter 139,820 km · Neptune 49,244 km
Width ratio
Jupiter is 2.8× wider
Volume
23 Neptunes fit inside Jupiter
Mass
Jupiter is 18.6× Neptune
Gravity (Jupiter · Neptune)
24.8 m/s² · 11.2 m/s²
Distance from Sun
5.2 AU · 30.1 AU
About 23 Neptunes would fit inside Jupiter by volume — and Jupiter would still out-weigh all of them together.
What sets them apart
Jupiter, the largest planet, against Neptune, the outermost. Jupiter is nearly three times Neptune’s width and around nineteen times its mass. Neptune is a dense ice giant; Jupiter is a hydrogen-helium colossus with no solid surface at all.
Ratios are easy to nod along to and impossible to picture. In the interactive view, switch to True scale to see Jupiter 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 Found something out of date?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.