The watt-hour
The watt-hour (Wh) equals 3,600 joules — the energy delivered by one watt of power over one hour. It is the natural unit for batteries, small electronics, and short-duration electrical loads.
Watt-hours to Calories Converter
1 Wh = 860.421 cal (watt-hour → calorie)
1 Wh = 860.421 cal
1 watt-hour equals 860.421 calories. To convert watt-hours to calories, multiply the watt-hour value by 860.421. For quick reference: 1 Wh = 860.421 cal, 5 Wh = 4302.1 cal, 10 Wh = 8604.21 cal, 100 Wh = 86042.1 cal.
Formula
Calories = Watt-hours × 860.421Quick
When to use watt-hours → calories
Watt-hours to small calories multiplies by 860.42 (3,600 J per Wh ÷ 4.184 J per thermochemical calorie). One watt-hour is 860.4 small calories — enough to warm 860 g of water by 1 °C, a handy sanity check for kettle and immersion-heater math. Note the output is physics calories: to express a battery's energy in food-Calorie terms, divide by a further 1,000. A 15 Wh phone battery is 12,906 small calories, but only about 12.9 kcal.
Cycling coaches comparing an e-bike's battery assist against a rider's own metabolic effort convert the motor's watt-hour draw into calories to place both energy sources on the same intuitive scale used in sports nutrition. A 300 Wh battery represents about 258,100 calories, dwarfing the roughly 500,000–800,000 small calories (500–800 kcal) a rider typically burns over a similar ride — a useful reminder that a small battery contains far more usable energy than a rider's own legs, even before accounting for motor and drivetrain losses.
How to convert watt-hours to calories
Take your value
Start with your value in watt-hours.
Multiply by 860.421
Multiply the watt-hour value by 860.421. This is the exact conversion factor from watt-hours to calories.
Read the result
The product is your value in calories. For example, 5 Wh × 860.421 = 4302.1 cal.
Conversion formula
The exact factor from watt-hours to calories is 860.421.
Calories = Watt-hours × 860.421
Watt-hours to Calories conversion table
Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.
| Watt-hours (Wh) | Calories (cal) |
|---|---|
| 0.001 Wh | 0.86042 cal |
| 0.01 Wh | 8.6042 cal |
| 0.1 Wh | 86.042 cal |
| 0.5 Wh | 430.21 cal |
| 1 Wh | 860.42 cal |
| 1.5 Wh | 1290.6 cal |
| 2 Wh | 1720.8 cal |
| 5 Wh | 4302.1 cal |
| 10 Wh | 8604.2 cal |
| 20 Wh | 17208 cal |
| 50 Wh | 43021 cal |
| 100 Wh | 86042 cal |
| 200 Wh | 172084 cal |
| 250 Wh | 215105 cal |
| 500 Wh | 430210 cal |
| 1000 Wh | 860421 cal |
| 2000 Wh | 1720841 cal |
| 2500 Wh | 2151052 cal |
| 3600 Wh | 3097514 cal |
| 5000 Wh | 4302103 cal |
| 7500 Wh | 6453155 cal |
| 10000 Wh | 8604207 cal |
| 25000 Wh | 21510516 cal |
| 50000 Wh | 43021033 cal |
| 100000 Wh | 86042065 cal |
| 250000 Wh | 215105163 cal |
| 500000 Wh | 430210325 cal |
| 1000000 Wh | 860420650 cal |
| 2000000 Wh | 1720841300 cal |
| 3600000 Wh | 3097514340 cal |
| 5000000 Wh | 4302103250 cal |
| 10000000 Wh | 8604206501 cal |
| 25000000 Wh | 21510516252 cal |
| 50000000 Wh | 43021032505 cal |
| 100000000 Wh | 86042065010 cal |
| 250000000 Wh | 215105162524 cal |
| 500000000 Wh | 430210325048 cal |
| 1000000000 Wh | 860420650096 cal |
| 2000000000 Wh | 1720841300191 cal |
| 5000000000 Wh | 4302103250478 cal |
| 10000000000 Wh | 8604206500956 cal |
| 20000000000 Wh | 17208413001912 cal |
| 50000000000 Wh | 43021032504780 cal |
| 100000000000 Wh | 86042065009560 cal |
| 1000000000000 Wh | 860420650095602 cal |
| 10000000000000 Wh | 8.6042 × 10^15 cal |
| 100000000000000 Wh | 8.6042 × 10^16 cal |
| 1000000000000000 Wh | 8.6042 × 10^17 cal |
| 10000000000000000 Wh | 8.6042 × 10^18 cal |
| 100000000000000000 Wh | 8.6042 × 10^19 cal |
Real-world reference
A typical smartphone battery stores about 15 Wh. An LED bulb uses 8 Wh per hour of operation. In calories, that gives you: 1 Wh = 860.421 cal, 10 Wh = 8604.21 cal, 100 Wh = 86042.1 cal.
Frequently asked questions
- How many calories are in 1 watt-hour?
- 1 watt-hour equals 860.421 calories.
- How do I convert watt-hours to calories?
- Multiply the watt-hour value by 860.421. So x Wh × 860.421 = the equivalent in cal.
- What is 5 watt-hours in calories?
- 5 watt-hours equals 4302.1 calories.
- What is 10 watt-hours in calories?
- 10 watt-hours equals 8604.21 calories.
- What is 100 watt-hours in calories?
- 100 watt-hours equals 86042.1 calories.
- How do I convert back from calories to watt-hours?
- Multiply the calorie value by 0.00116222. For example, 1 cal = 0.00116222 Wh.
- Is the watt-hour bigger than the calorie?
- Yes. 1 watt-hour is larger than 1 calorie — specifically 860.421 times larger.
- Are these conversion factors exact?
- The factor is derived directly from the SI definitions of watt-hour and calorie; the displayed value is rounded for readability, and the browser computes using IEEE 754 double-precision arithmetic.
About the watt-hour and the calorie
The calorie
Convertitive uses the thermochemical (small) calorie, defined as exactly 4.184 joules — the energy needed to raise 1 g of water by 1 °C. Do not confuse it with the large calorie (kcal) used on US nutrition labels, which is 1,000 of these small calories.