Calculator
What the Electron Volt Converter does
Electron Volt Converter: 1 eV = 1.602177e-19 J, so multiply a electronvolt value by 1.602177e-19 to get joule, or divide to go back. Example: 1 eV = 1.602177e-19 J.
Feed it Value, From and To; it hands back Result, How it was calculated and Reverse conversion. Adjust anything and the figures re-derive on the spot.
Most people who open the Electron Volt Converter are students converting units for homework. Unit mistakes are quietly expensive. They have wrecked spacecraft and ruined recipes alike.
The page holds your values in memory and forgets them the moment you close it.
Below the tool you will find the field reference, the method, and an example computed from the values it opens with.
What do the Electron Volt Converter fields mean?
The Electron Volt Converter uses 3 inputs. The page opens in a usable state: real values in, real answer out, ready to edit.
| Field | What to enter | Default |
|---|---|---|
| Value | required | 1 |
| From | choose from Joule (J), Kilojoule (kJ), Megajoule (MJ), Calorie (thermochemical) (cal), Kilocalorie (food calorie) (kcal) or Watt hour (Wh) | Electronvolt (eV) |
| To | choose from Joule (J), Kilojoule (kJ), Megajoule (MJ), Calorie (thermochemical) (cal), Kilocalorie (food calorie) (kcal) or Watt hour (Wh) | Joule (J) |
How does the Electron Volt Converter work?
Both units are converted through energy's base unit (J), so any of the 12 units in the dropdowns can be paired in either direction without loss of accuracy.
Exact definitions are preferred throughout: the metre, the inch and the pound all have them. Only where a unit depends on a measured constant is an accepted published value substituted.
Worked example
These are the values the Electron Volt Converter loads by default, and the result it produces from them. Below is the same computation the tool performs on load, step by step.
| Value | 1 |
|---|---|
| From | Electronvolt (eV) |
| To | Joule (J) |
| Result | 1.602177e-19 J |
|---|---|
| How it was calculated | 1 eV = 1.602177e-19 J, so 1 × 1.602177e-19 = 1.602177e-19 J |
| Reverse conversion | 6.241509e+18 eV (if you meant 1 J) |
The electronvolt
An electronvolt (eV) equals exactly 1.602176634 × 10⁻¹⁹ joules: an extraordinarily tiny unit of energy, and one of the few quantities on this site that has been an exact defined value only since the 2019 redefinition of the SI, which fixed the elementary electric charge at exactly this same numeric value in coulombs.
Worth knowing
- It’s the natural energy scale for atomic and subatomic physics: chemical bond energies are typically a few eV, visible-light photons carry roughly 1.6 to 3.2 eV each, and nuclear reactions release energies in the millions of eV (MeV) or even billions (GeV) range.
- Because it’s tied to the elementary charge (the charge of a single electron or proton) rather than to a macroscopic reference like water or a mechanical force, it scales naturally with the size of individual atoms and particles in a way joules don’t conveniently express.
- Particle accelerators are often described by the energy they impart, measured in GeV or TeV (billions or trillions of electronvolts). The Large Hadron Collider, for instance, accelerates particles to energies of several TeV, an almost incomprehensibly large number of individual electronvolts.
Definitions: BIPM SI Brochure · NIST reference on units
How to use it
- Type Value.
- Pick a value for From: the options are Joule (J), Kilojoule (kJ), Megajoule (MJ), Calorie (thermochemical) (cal), Kilocalorie (food calorie) (kcal) or Watt hour (Wh).
- Pick a value for To: the options are Joule (J), Kilojoule (kJ), Megajoule (MJ), Calorie (thermochemical) (cal), Kilocalorie (food calorie) (kcal) or Watt hour (Wh).
- The answer follows your cursor, in effect. Change a field and read the new figure.
- Look at Result, How it was calculated and Reverse conversion in the output panel.
- Copy Link when you want to return to this exact configuration; Print when someone needs it on paper.
What this tool does not do
- Factors use the internationally agreed definitions; some industries round them differently.
- Repeated conversions compound rounding, so convert once from the original value where you can.
- The tool answers exactly the question it is given; it cannot know the context around your numbers.
- Nothing here can catch a correct number entered in the wrong field.
Frequently asked questions
The form asks for Value, From and To. Every box already holds a working value, so the quickest approach is to replace the one number you actually care about.
With the values loaded when the page opens, result comes out as 1.602177e-19 J. Adjust any field to see how much the answer depends on it.
No record is kept. We never receive what you type, so there is nothing on our side to retain.
No charge. Everything on the page is available without signing in.
As accurate as the inputs allow. The arithmetic itself introduces no error beyond display rounding.