Jupiter Mass to Earth Mass Converter

Enter a value and pick the conversion direction.

Result

0.2989 MJ
317.8 M⊕ = 1 MJ
95.00 M⊕

How it is calculated

The tool uses one fixed ratio, 1 MJ = 317.8 M⊕, where MJ is one Jupiter mass and M⊕ one Earth mass. Choose the direction. From Jupiter to Earth masses it computes M⊕ = MJ × 317.8 and shows 2 decimals. From Earth to Jupiter masses it computes MJ = M⊕ ÷ 317.8 and shows 4 decimals, but a tiny non-zero result keeps three significant digits instead of printing 0.0000 (0.001 M⊕ shows 0.00000315 MJ). The result also repeats your input and shows the rate used. Negative values and unknown directions give no result, and zero converts to zero. Because the ratio is a single rounded constant, the answer is only as exact as 317.8 is; very precise work should use the exact masses in kilograms from the data source.

Worked example

A planet is listed at 95 Earth masses and you want it in Jupiter masses, so choose the Earth-to-Jupiter direction. The division is 95 ÷ 317.8 = 0.29893..., which the tool shows as 0.2989 MJ. It also repeats the input as 95.00 M⊕ and prints the rate 317.8 M⊕ = 1 MJ. The planet therefore has roughly 30% of Jupiter's mass. Going back, 0.2989 × 317.8 gives about 94.99, a small difference caused by rounding.

Try this example →

Common mistakes

  • Leaving the direction on the default. The default converts Jupiter masses to Earth masses; if you typed an Earth-mass value and forgot to switch, the result is 317.8 times too large.
  • Confusing mass with radius or volume. 1 Jupiter radius is not 317.8 Earth radii, and the ratio here applies to mass only.
  • Converting back from the rounded result and expecting the original number. 0.2989 MJ converts back to 94.99 M⊕, not 95, because only four decimals are shown.
  • Typing a mass in kilograms or in solar masses. The input is only a count of Jupiter or Earth masses; convert other units first.
  • Comparing a rounded result with a catalogue value to the last digit. The constant 317.8 is itself rounded, so small differences from published figures are normal.

About this calculator

Astronomers use Jupiter mass (M_J) as a convenient standard unit for large planetary bodies, since expressing an exoplanet's mass directly in kilograms produces unwieldy numbers — one Jupiter mass equals roughly 317.8 Earth masses (about 1.898 × 10²⁷ kg). This converter moves between the two units in either direction, letting a mass expressed for a gas giant be compared directly against Earth-scale references.

The conversion is used constantly in exoplanet science and astronomy, where discovery papers and databases like NASA's Exoplanet Archive typically report giant-planet masses in Jupiter masses and terrestrial-planet masses in Earth masses — converting between the two lets researchers, students, and space enthusiasts compare a newly discovered planet's bulk directly against familiar solar system benchmarks.

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