What is one electronvolt (eV) in joules?
One electronvolt equals 1 eV = 1.602176634e-19 J exactly, numerically equal to the elementary charge in coulombs. 1 MeV = 1.602176634e-13 J.
Open the interactive PhysRef tool →Key facts
| Value | 1 eV = 1.602176634e-19 J |
|---|---|
| 1 keV | 1.602176634e-16 J |
| 1 MeV | 1.602176634e-13 J |
| 1 GeV | 1.602176634e-10 J |
| Source | CODATA 2018 |
Frequently asked questions
How many joules is 1 eV?
1 eV = 1.602176634e-19 J, exactly equal to the elementary charge times one volt.
How big is 1 MeV in joules?
1 MeV = 1.602176634e-13 J, one million electronvolts.
Why use electronvolts?
In atomic and particle physics, energies are tiny in joules, so the convenient eV unit (charge × volt) is used instead.
Related pages
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