How to Convert Electronvolts to Watt-hours (eV to Wh)
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 electronvolts into watt-hours by hand, with examples and a quick-reference table.
The conversion
To convert electronvolts to watt-hours, multiply the value by 4.450491e-23. To go the other way, divide by the same number (or multiply by 2.246943e+22). Because the factor is tiny, scientific notation keeps the numbers manageable.
Watt-hours = electronvolts × 4.450491e-23
Worked examples
- 3 eV = 1.335147e-22 Wh
- 12.5 eV = 5.563113e-22 Wh
- 75 eV = 3.337868e-21 Wh
Electronvolts to Watt-hours table
| Electronvolts | Watt-hours |
|---|---|
| 1 eV | 4.450491e-23 Wh |
| 2 eV | 8.900981e-23 Wh |
| 5 eV | 2.225245e-22 Wh |
| 10 eV | 4.450491e-22 Wh |
| 20 eV | 8.900981e-22 Wh |
| 25 eV | 1.112623e-21 Wh |
| 50 eV | 2.225245e-21 Wh |
| 100 eV | 4.450491e-21 Wh |
| 250 eV | 1.112623e-20 Wh |
| 500 eV | 2.225245e-20 Wh |
| 1,000 eV | 4.450491e-20 Wh |
Common questions
Is eV to Wh 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 Watt-hours to Electronvolts converter.
Mistakes to avoid
Dropping the units
A bare number without a unit is easy to misread later. Always write the unit with the result.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Multiplying when you should divide
Converting to a smaller unit gives a bigger number, and converting to a larger unit gives a smaller one. If your answer moves the wrong way, you have inverted the factor.
Background
Writing the units next to every number while you work is the simplest way to avoid mistakes. If the units do not cancel to leave the one you want, the calculation is set up wrongly.
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.
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
For any value, use the Electronvolts to Watt-hours Converter or browse all energy converters.
Run your own numbers: Electronvolts to Watt-hours Converter