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Energy
Watt-hours to Calories
Convert watt-hours (Wh) to calories (cal). Type a value below to see the result update instantly. Reference table and formula included.
Calculator
1 Wh = 860.42 cal
Watt-hours to Calories Conversion Table
Common values, ready to copy:
| watt-hours | calories |
|---|---|
| 1 Wh | 860.42 cal |
| 2 Wh | 1720.84 cal |
| 5 Wh | 4302.1 cal |
| 10 Wh | 8604.21 cal |
| 25 Wh | 21510.52 cal |
| 50 Wh | 43021.03 cal |
| 100 Wh | 86042.07 cal |
| 1,000 Wh | 860420.65 cal |
Formula
calories = watt-hours × 8.60420650e+2
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
About Watt-hours and Calories
Watt-hours (Wh): The energy consumed by a 1-watt device in 1 hour; equals 3,600 joules. Common uses: Small battery capacities (laptop batteries are typically 40-100 Wh), and lighting energy use.
Calories (cal): Originally defined as the energy to raise one gram of water by one degree Celsius; exactly 4.184 J in the modern definition (the thermochemical calorie). Common uses: Scientific work in chemistry, where the small calorie is the natural unit for heat-of-reaction measurements.
How the conversion works
Energy uses the SI joule. Food calories (kcal) are 1,000 small calories: 1 kcal = 4,184 J. 1 kWh = 3.6 MJ = 3,600,000 J. 1 BTU = 1,055.06 J.
The exact relationship is calories = watt-hours × 8.60420650e+2, which the calculator at the top of this page applies in both directions. Type into either field and the other updates immediately.
When this conversion matters
Converting between watt-hours and calories comes up wherever energy measurements move between systems — from one country's conventions to another's, from a scientific reference to a practical specification, or from one industry's working unit to another's. The calculator and reference table above cover the everyday range; for unusual values you can type any number into either field.