Convert Calories to Watt-hours
1 calorie is 0.001162 Wh. One calorie is exactly 0.00116222222222 watt-hours.
One calorie is 0.0011622222 watt-hours. To convert calories to watt-hours, multiply by 0.0011622222; to go the other way, divide by 0.0011622222 or multiply by 860.42065. The factor is exact rather than rounded: it follows from NIST Special Publication 811. The thermochemical calorie: exactly 4.184 joules by definition.
Factor checked against the defining standard · How we check
- Calories × 0.0011622222
value * 0.001162222222220.001 Wh
1 calorie in every energy unit
| Unit | Value | Exact factor |
|---|---|---|
| joules | 4.184 J | × 4.184 |
| kilojoules | 0.004184 kJ | × 0.004184 |
| calories (as entered) | 1 cal | — |
| kilocalories | 0.001 kcal | × 0.001 |
| watt-hours | 0.001162222222 Wh | × 0.00116222222222 |
| kilowatt-hours | 0.000001162222222 kWh | × 0.00000116222222222 |
| British thermal units | 0.003965666831 BTU | × 0.00396566683139 |
| foot-pounds | 3.085960033 ft·lbf | × 3.08596003258 |
Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert calories to watt-hours?
- 1.Take the measurement in calories.
- 2.Multiply by 0.0011622222 — that is how many watt-hours fit in one calorie.
- 3.To go back the other way, divide by 0.0011622222, or multiply by 860.42065.
Worked example: 25 calories to watt-hours
- Formula
- cal × 0.0011622222 = Wh
- Arithmetic
- 25 × 0.0011622222 = 0.029056 Wh
- Answer
- 25 cal = 0.029056 Wh
The factor is rounded for display; the figure above is computed from the full value.
Calories to watt-hours conversion table
| Calories | Watt-hours |
|---|---|
| 1 cal | 0.001162 Wh |
| 2 cal | 0.002324 Wh |
| 3 cal | 0.003487 Wh |
| 4 cal | 0.004649 Wh |
| 5 cal | 0.005811 Wh |
| 6 cal | 0.006973 Wh |
| 7 cal | 0.008136 Wh |
| 8 cal | 0.009298 Wh |
| 9 cal | 0.01046 Wh |
| 10 cal | 0.011622 Wh |
| 12 cal | 0.013947 Wh |
| 15 cal | 0.017433 Wh |
| 20 cal | 0.023244 Wh |
| 25 cal | 0.029056 Wh |
| 50 cal | 0.058111 Wh |
| 100 cal | 0.116222 Wh |
| 200 cal | 0.232444 Wh |
| 300 cal | 0.348667 Wh |
| 500 cal | 0.581111 Wh |
| 1000 cal | 1.162222 Wh |
| 2000 cal | 2.324444 Wh |
| 5000 cal | 5.811111 Wh |
| 10000 cal | 11.622222 Wh |
What is a calorie?
The thermochemical calorie: exactly 4.184 joules by definition. This is the small calorie — the one on a food label is a thousand of these, which is the single most common confusion in this group.
What is a watt-hour?
One watt sustained for an hour, so exactly 3,600 joules. Battery capacity is quoted here because it is an amount of energy rather than a rate.
How many watt-hours are in a calorie?
One calorie is 0.0011622222 watt-hours. Going the other way, one watt-hour is 860.42065 calories. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every energy unit here
| Unit | Symbol | One of these is |
|---|---|---|
| Joules | J | the base unit |
| Kilojoules | kJ | 1000 joule |
| Calories | cal | 4.184 joule |
| Kilocalories | kcal | 4184 joule |
| Watt-hours | Wh | 3600 joule |
| Kilowatt-hours | kWh | 3600000 joule |
| British thermal units | BTU | 1055.0559 joule |
| Foot-pounds | ft·lbf | 1.3558179 joule |
Source: NIST Special Publication 811 — the thermochemical calorie is exactly 4.184 J
Questions people actually ask
- How many watt-hours are in a calorie?
- 0.0011622222. One watt sustained for an hour, so exactly 3,600 joules. Battery capacity is quoted here because it is an amount of energy rather than a rate.
- How do I convert watt-hours back to calories?
- Divide by 0.0011622222, or multiply by 860.42065 — they are the same operation.
Other energy conversions
Watt-hours to calories — the same conversion the other way.