Convert British thermal units to Watt-hours
1 British thermal unit is 0.293071 Wh. One British thermal unit is exactly 0.293071070172 watt-hours.
One British thermal unit is 0.29307107 watt-hours. To convert British thermal units to watt-hours, multiply by 0.29307107; to go the other way, divide by 0.29307107 or multiply by 3.4121416. The factor is exact rather than rounded: it follows from NIST Special Publication 811. The international-table BTU, fixed at exactly 1055.05585262 joules.
Factor checked against the defining standard · How we check
- British thermal units × 0.29307107
value * 0.2930710701720.293 Wh
1 British thermal unit in every energy unit
| Unit | Value | Exact factor |
|---|---|---|
| joules | 1,055.055853 J | × 1,055.05585262 |
| kilojoules | 1.055055853 kJ | × 1.05505585262 |
| calories | 252.1644007 cal | × 252.164400722 |
| kilocalories | 0.2521644007 kcal | × 0.252164400722 |
| watt-hours | 0.2930710702 Wh | × 0.293071070172 |
| kilowatt-hours | 0.0002930710702 kWh | × 0.000293071070172 |
| British thermal units (as entered) | 1 BTU | — |
| foot-pounds | 778.1692623 ft·lbf | × 778.169262266 |
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 British thermal units to watt-hours?
- 1.Take the measurement in British thermal units.
- 2.Multiply by 0.29307107 — that is how many watt-hours fit in one British thermal unit.
- 3.To go back the other way, divide by 0.29307107, or multiply by 3.4121416.
Worked example: 25 British thermal units to watt-hours
- Formula
- BTU × 0.29307107 = Wh
- Arithmetic
- 25 × 0.29307107 = 7.326777 Wh
- Answer
- 25 BTU = 7.326777 Wh
The factor is rounded for display; the figure above is computed from the full value.
British thermal units to watt-hours conversion table
| British thermal units | Watt-hours |
|---|---|
| 1 BTU | 0.293071 Wh |
| 2 BTU | 0.586142 Wh |
| 3 BTU | 0.879213 Wh |
| 4 BTU | 1.172284 Wh |
| 5 BTU | 1.465355 Wh |
| 6 BTU | 1.758426 Wh |
| 7 BTU | 2.051497 Wh |
| 8 BTU | 2.344569 Wh |
| 9 BTU | 2.63764 Wh |
| 10 BTU | 2.930711 Wh |
| 12 BTU | 3.516853 Wh |
| 15 BTU | 4.396066 Wh |
| 20 BTU | 5.861421 Wh |
| 25 BTU | 7.326777 Wh |
| 50 BTU | 14.653554 Wh |
| 100 BTU | 29.307107 Wh |
| 200 BTU | 58.614214 Wh |
| 300 BTU | 87.921321 Wh |
| 500 BTU | 146.535535 Wh |
| 1000 BTU | 293.07107 Wh |
| 2000 BTU | 586.14214 Wh |
| 5000 BTU | 1,465.355351 Wh |
| 10000 BTU | 2,930.710702 Wh |
What is a British thermal unit?
The international-table BTU, fixed at exactly 1055.05585262 joules. Roughly the heat needed to raise a pound of water by one degree Fahrenheit, which is where it came from.
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 British thermal unit?
One British thermal unit is 0.29307107 watt-hours. Going the other way, one watt-hour is 3.4121416 British thermal units. 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 British thermal unit?
- 0.29307107. 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 British thermal units?
- Divide by 0.29307107, or multiply by 3.4121416 — they are the same operation.
Other energy conversions
Watt-hours to British thermal units — the same conversion the other way.