Electronvolts to Joules

1 electronvolt = 1.602176634 × 10^-19 joules exactly. Type in either box; the other updates as you go.

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ElectronvoltseVJoulesJ

13.6 eV = 0.00000000000000000217896 JJ = eV × 1.602176634e-19 · shown to 6 significant figures

Precision

Quick reference

eV	J
1	0.000000000000000000160218
2	0.000000000000000000320435
5	0.000000000000000000801088
10	0.00000000000000000160218
20	0.00000000000000000320435
50	0.00000000000000000801088
100	0.0000000000000000160218
1,000	0.000000000000000160218

Electronvolts and joules

The electronvolt is the energy an electron gains across one volt: exactly 1.602176634 × 10⁻¹⁹ joules since 2019. Particle physics, chemistry and semiconductor band gaps use electronvolts.

The joule is the SI unit of energy: the work done by a force of one newton over one meter, or one watt for one second. Physics, engineering and EU food labels (as kJ) use joules.

Worked example

Convert 13.6 eV: 13.6 × 1.602176634 × 10^-19 = 2.178960222 × 10^-18, so 13.6 electronvolts is 2.178960222 × 10^-18 joules. Likewise 20 eV = 3.204353268 × 10^-18 J.

Estimating in your head

Divide by 6.2 × 10^18 for a quick figure; it is off by about 0.7%. For 13.6 eV that gives 2.19 J, against 2.17896 × 10^-18 exactly.

Going the other way

To convert joules to electronvolts, divide by 1.602176634 × 10^-19 (or multiply by about 6.241509074 × 10^18). The swap button between the boxes opens that page.

How this works

J = eV × 1.602176634 × 10^-19

1 eV = 1.602176634 × 10^-19 J and 1 J = 1 J, both by definition, so the factor is their ratio: 1.602176634 × 10^-19 exactly. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.

Frequently asked

How many joules are in a electronvolt?

1 electronvolt = 1.602176634 × 10^-19 joules, exactly. The value follows from the unit definitions, so it never changes.

How do I convert electronvolts to joules?

Multiply by 1.602176634 × 10^-19. For example, 20 eV × 1.602176634 × 10^-19 = 3.204353268 × 10^-18 J.

What is 100 eV in joules?

100 eV = 1.602176634 × 10^-17 J. The table next to the converter lists more common values.

Is the result rounded?

Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.

Sources

Reviewed Oct 17, 2026 · test vectors fixtures/units/energy/ev-to-joules/