How long is a day on Neptune?
Data as of July 2026
16 h 7 minone full spin
A day on Neptune lasts 16 h 7 min. That is 67% of an Earth day. Neptune has no solid surface, so its day is the time the planet takes to turn once.
▶ Watch Neptune turn in 3D
Why Neptune's day is so short
Neptune's day was first timed by Voyager 2 in 1989 from the planet's radio emissions. Its cloud bands do not keep that time: at the equator the winds blow so fast against the spin that clouds lap the planet more slowly than the planet itself turns.
Sunrise to sunrise
16 h 7 min
One spin (against the stars)
16 h 7 min
Compared with Earth
67% of an Earth day
Neptune days in its year
about 89,700
Its year
165 Earth years
Distance from the Sun
30.1 AU
Day length on every world
| World | Day (sunrise to sunrise) | One spin |
|---|---|---|
| Jupiter | 9 h 56 min | 9 h 56 min |
| Saturn | 10 h 39 min | 10 h 39 min |
| Neptune | 16 h 7 min | 16 h 7 min |
| Uranus | 17 h 14 min | 17 h 14 min (backwards) |
| Earth | 24 h 0 min | 23 h 56 min |
| Mars | 24 h 40 min | 24 h 37 min |
| Pluto | 6.4 Earth days | 6.4 Earth days (backwards) |
| Venus | 117 Earth days | 243 Earth days (backwards) |
| Mercury | 176 Earth days | 58.6 Earth days |
Earth's spin, against the stars, takes 23 h 56 min; the extra four minutes to a 24-hour day come from Earth moving along its orbit while it turns. On Neptune the same effect is too small to matter.
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 Found something out of date?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.