How to Convert Watt-hours to Calories (Wh to cal)
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 watt-hours into calories by hand, with examples and a quick-reference table.
The conversion
To convert watt-hours to calories, multiply the value by 860.4206500956. To go the other way, divide by the same number (or multiply by 0.0011622222). For a quick estimate, multiply by about 860.
Calories = watt-hours × 860.4206500956
Worked examples
- 3 Wh = 2,581.26 cal
- 12.5 Wh = 10,755.26 cal
- 75 Wh = 64,531.55 cal
Watt-hours to Calories table
| Watt-hours | Calories |
|---|---|
| 1 Wh | 860.4207 cal |
| 2 Wh | 1,720.84 cal |
| 5 Wh | 4,302.1 cal |
| 10 Wh | 8,604.21 cal |
| 20 Wh | 17,208.41 cal |
| 25 Wh | 21,510.52 cal |
| 50 Wh | 43,021.03 cal |
| 100 Wh | 86,042.07 cal |
| 250 Wh | 215,105.16 cal |
| 500 Wh | 430,210.33 cal |
| 1,000 Wh | 860,420.65 cal |
Common questions
Is Wh to cal 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 Calories to Watt-hours converter.
Mistakes to avoid
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
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
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.
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.
Many conversion factors are exact by definition. The inch has been defined as exactly 2.54 centimetres since 1959, and the pound as exactly 0.45359237 kilograms, so conversions involving them can be as precise as you need.
For any value, use the Watt-hours to Calories Converter or browse all energy converters.
Run your own numbers: Watt-hours to Calories Converter