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Mass of Neptune

MNeptune=1.02413×1026 kgM_{\mathrm{Neptune}} = 1.02413 \times 10^{26}\ \text{kg}
Value17.1482870634 Mearth (1.02413 × 10²⁶ kg)
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StatusMeasured: ± 3.9 × 10⁻⁴ Mearth (2.2 × 10⁻⁵ relative), standard uncertainty
SourceNASA planetary fact sheet; GM from Voyager 2 tracking and satellite orbits, divided by CODATA 2022 G
CategoriesAstronomicalPlanets
Mass of Neptune in every mass unit
UnitValue
Earth mass17.148287 Mearth
28 more mass units
unified atomic mass unit (dalton)6.1674550e+52 u
picogram1.0241300e+41 pg
nanogram1.0241300e+38 ng
microgram1.0241300e+35 μg
milligram1.0241300e+32 mg
centigram1.0241300e+31 cg
grain1.5804741e+30 gr
metric carat5.1206500e+29 ct
gram1.0241300e+29 g
pennyweight6.5853088e+28 dwt
dram5.7800196e+28 dr
ounce3.6125123e+27 oz
troy ounce3.2926544e+27 oz t
troy pound2.7438787e+26 lb t
pound2.2578202e+26 lb
kilogram1.0241300e+26 kg
stone1.6127287e+25 st
slug7.0175196e+24 slug
US hundredweight2.2578202e+24 cwt
UK long hundredweight2.0159109e+24 cwt (UK)
quintal1.0241300e+24 q
US short ton1.1289101e+23 ton
metric tonne1.0241300e+23 t
UK long ton1.0079554e+23 long ton
kilotonne1.0241300e+20 kt
megatonne1.0241300e+17 Mt
gigatonne102,413,000,000,000 Gt
solar mass0.000051504971 Msun

Learning zone

Neptune was predicted before it was seen. Discrepancies in Uranus's orbit led Le Verrier to calculate the position of a perturbing body, and Galle at the Berlin Observatory found it on the first night of looking, 23 September 1846, less than a degree from the predicted spot. Galileo had recorded it as a star in 1613 without noticing it moved.

Slightly smaller than Uranus but appreciably more massive, Neptune has the highest density of the four giants and radiates 2.6 times the energy it receives from the Sun, driving the fastest winds in the solar system at over 2000 km/h. Its own gravity governs the Kuiper belt: Pluto and the plutinos are locked in a 3:2 resonance with Neptune's 165-year orbit, which is what keeps them from ever colliding with it.

Used by 4 solvers

Escape Velocity

v=2GMrv = \sqrt{\frac{2GM}{r}}

Gravitational Field Strength

g=GMr2g = \frac{GM}{r^{2}}

Orbital Period

T=2πr3GMT = 2\pi \sqrt{\frac{r^{3}}{GM}}

Orbital Velocity

v=GMrv = \sqrt{\frac{GM}{r}}
Revised 16 October 2026
Cite this page

formula.expert. (2026, October 16). Mass of Neptune. https://formula.expert/constants/neptune-mass