Convert Watt-hours to British thermal units
1 watt-hour is 3.412142 BTU. One watt-hour is exactly 3.41214163313 British thermal units.
One watt-hour is 3.4121416 British thermal units. To convert watt-hours to British thermal units, multiply by 3.4121416; to go the other way, divide by 3.4121416 or multiply by 0.29307107. The factor is exact rather than rounded: it follows from NIST Special Publication 811. One watt sustained for an hour, so exactly 3,600 joules.
Factor checked against the defining standard · How we check
- Watt-hours × 3.4121416
value * 3.412141633133.412 BTU
1 watt-hour in every energy unit
| Unit | Value | Exact factor |
|---|---|---|
| joules | 3,600 J | × 3,600 |
| kilojoules | 3.6 kJ | × 3.6 |
| calories | 860.4206501 cal | × 860.420650096 |
| kilocalories | 0.8604206501 kcal | × 0.860420650096 |
| watt-hours (as entered) | 1 Wh | — |
| kilowatt-hours | 0.001 kWh | × 0.001 |
| British thermal units | 3.412141633 BTU | × 3.41214163313 |
| foot-pounds | 2,655.223737 ft·lbf | × 2,655.2237374 |
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 watt-hours to British thermal units?
- 1.Take the measurement in watt-hours.
- 2.Multiply by 3.4121416 — that is how many British thermal units fit in one watt-hour.
- 3.To go back the other way, divide by 3.4121416, or multiply by 0.29307107.
Worked example: 25 watt-hours to British thermal units
- Formula
- Wh × 3.4121416 = BTU
- Arithmetic
- 25 × 3.4121416 = 85.303541 BTU
- Answer
- 25 Wh = 85.303541 BTU
The factor is rounded for display; the figure above is computed from the full value.
Watt-hours to British thermal units conversion table
| Watt-hours | British thermal units |
|---|---|
| 1 Wh | 3.412142 BTU |
| 2 Wh | 6.824283 BTU |
| 3 Wh | 10.236425 BTU |
| 4 Wh | 13.648567 BTU |
| 5 Wh | 17.060708 BTU |
| 6 Wh | 20.47285 BTU |
| 7 Wh | 23.884991 BTU |
| 8 Wh | 27.297133 BTU |
| 9 Wh | 30.709275 BTU |
| 10 Wh | 34.121416 BTU |
| 12 Wh | 40.9457 BTU |
| 15 Wh | 51.182124 BTU |
| 20 Wh | 68.242833 BTU |
| 25 Wh | 85.303541 BTU |
| 50 Wh | 170.607082 BTU |
| 100 Wh | 341.214163 BTU |
| 200 Wh | 682.428327 BTU |
| 300 Wh | 1,023.64249 BTU |
| 500 Wh | 1,706.070817 BTU |
| 1000 Wh | 3,412.141633 BTU |
| 2000 Wh | 6,824.283266 BTU |
| 5000 Wh | 17,060.708166 BTU |
| 10000 Wh | 34,121.416331 BTU |
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.
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.
How many British thermal units are in a watt-hour?
One watt-hour is 3.4121416 British thermal units. Going the other way, one British thermal unit is 0.29307107 watt-hours. 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 British thermal units are in a watt-hour?
- 3.4121416. 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.
- How do I convert British thermal units back to watt-hours?
- Divide by 3.4121416, or multiply by 0.29307107 — they are the same operation.
Other energy conversions
British thermal units to watt-hours — the same conversion the other way.