How to Convert Joules to Electronvolts (J to eV)
Energy conversions link food labels in kJ and kcal, SP Group bills in kWh and air-conditioner capacity in BTU. This guide shows how to convert joules into electronvolts by hand, with examples and a quick-reference table.
The conversion
To convert joules to electronvolts, multiply the value by 6.241509e+18. To go the other way, divide by the same number (or multiply by 1.602177e-19). For a quick estimate, multiply by about 6,200,000,000,000,000,000.
Electronvolts = joules × 6.241509e+18
Worked examples
- 3 J = 1.872453e+19 eV
- 12.5 J = 7.801886e+19 eV
- 75 J = 4.681132e+20 eV
Joules to Electronvolts table
| Joules | Electronvolts |
|---|---|
| 1 J | 6.241509e+18 eV |
| 2 J | 1.248302e+19 eV |
| 5 J | 3.120755e+19 eV |
| 10 J | 6.241509e+19 eV |
| 20 J | 1.248302e+20 eV |
| 25 J | 1.560377e+20 eV |
| 50 J | 3.120755e+20 eV |
| 100 J | 6.241509e+20 eV |
| 250 J | 1.560377e+21 eV |
| 500 J | 3.120755e+21 eV |
| 1,000 J | 6.241509e+21 eV |
Common questions
Is J to eV exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Electronvolts to Joules converter.
Mistakes to avoid
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Background
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.
For any value, use the Joules to Electronvolts Converter or browse all energy converters.
Run your own numbers: Joules to Electronvolts Converter