The Jupiter mass, also called Jovian mass, is the unit of mass equal to the total mass of the planet Jupiter. This value may refer to the mass of the planet alone, or the mass of the entire Jovian system to include the moons of Jupiter. Jupiter is by far the most massive planet in the Solar System. It is approximately 2.5 times as massive as all of the other planets in the Solar System combined.

Jupiter mass is a common unit of mass in astronomy that is used to indicate the masses of other similarly-sized objects, including the outer planets, extrasolar planets, and brown dwarfs, as this unit provides a convenient scale for comparison.

The current best known value for the mass of Jupiter can be expressed as 1898130 yottagrams:

$${\displaystyle M_{\mathrm {J} }=(1.89813\pm 0.00019)\times 10^{27}{\text{ kg}},}$$

which is about 1⁄1000 as massive as the Sun (is about 0.1% M_☉):

$${\displaystyle M_{\mathrm {J} }={\frac {1}{1047.348644\pm 0.000017}}M_{\odot }\approx (9.547919\pm 0.000002)\times 10^{-4}M_{\odot }.}$$

Jupiter is 318 times as massive as Earth:

$${\displaystyle M_{\mathrm {J} }=3.1782838\times 10^{2}M_{\oplus }.}$$