Convert British thermal units to Joules
1 British thermal unit is 1,055.055853 J. One British thermal unit is exactly 1055.05585262 joules.
One British thermal unit is 1055.0559 joules. To convert British thermal units to joules, multiply by 1055.0559; to go the other way, divide by 1055.0559 or multiply by 9.4782 × 10^-4. 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 × 1055.0559
value * 1055.055852621,055.056 J
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 joules?
- 1.Take the measurement in British thermal units.
- 2.Multiply by 1055.0559 — that is how many joules fit in one British thermal unit.
- 3.To go back the other way, divide by 1055.0559, or multiply by 9.4782 × 10^-4.
Worked example: 25 British thermal units to joules
- Formula
- BTU × 1055.0559 = J
- Arithmetic
- 25 × 1055.0559 = 26,376.396316 J
- Answer
- 25 BTU = 26,376.396316 J
The factor is rounded for display; the figure above is computed from the full value.
British thermal units to joules conversion table
| British thermal units | Joules |
|---|---|
| 1 BTU | 1,055.055853 J |
| 2 BTU | 2,110.111705 J |
| 3 BTU | 3,165.167558 J |
| 4 BTU | 4,220.22341 J |
| 5 BTU | 5,275.279263 J |
| 6 BTU | 6,330.335116 J |
| 7 BTU | 7,385.390968 J |
| 8 BTU | 8,440.446821 J |
| 9 BTU | 9,495.502674 J |
| 10 BTU | 10,550.558526 J |
| 12 BTU | 12,660.670231 J |
| 15 BTU | 15,825.837789 J |
| 20 BTU | 21,101.117052 J |
| 25 BTU | 26,376.396316 J |
| 50 BTU | 52,752.792631 J |
| 100 BTU | 105,505.585262 J |
| 200 BTU | 211,011.170524 J |
| 300 BTU | 316,516.755786 J |
| 500 BTU | 527,527.92631 J |
| 1000 BTU | 1,055,055.85262 J |
| 2000 BTU | 2,110,111.70524 J |
| 5000 BTU | 5,275,279.2631 J |
| 10000 BTU | 10,550,558.5262 J |
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 joule?
The SI unit: one newton acting through one metre. Dropping a small apple one metre releases about one joule.
How many joules are in a British thermal unit?
One British thermal unit is 1055.0559 joules. Going the other way, one joule is 9.4782 × 10^-4 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 joules are in a British thermal unit?
- 1055.0559. The SI unit: one newton acting through one metre. Dropping a small apple one metre releases about one joule.
- How do I convert joules back to British thermal units?
- Divide by 1055.0559, or multiply by 9.4782 × 10^-4 — they are the same operation.
Other energy conversions
Joules to British thermal units — the same conversion the other way.