Convert British thermal units to Kilojoules
1 British thermal unit is 1.055056 kJ. One British thermal unit is exactly 1.05505585262 kilojoules.
One British thermal unit is 1.0550559 kilojoules. To convert British thermal units to kilojoules, multiply by 1.0550559; to go the other way, divide by 1.0550559 or multiply by 0.94781712. 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 × 1.0550559
value * 1.055055852621.055 kJ
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 kilojoules?
- 1.Take the measurement in British thermal units.
- 2.Multiply by 1.0550559 — that is how many kilojoules fit in one British thermal unit.
- 3.To go back the other way, divide by 1.0550559, or multiply by 0.94781712.
Worked example: 25 British thermal units to kilojoules
- Formula
- BTU × 1.0550559 = kJ
- Arithmetic
- 25 × 1.0550559 = 26.376396 kJ
- Answer
- 25 BTU = 26.376396 kJ
The factor is rounded for display; the figure above is computed from the full value.
British thermal units to kilojoules conversion table
| British thermal units | Kilojoules |
|---|---|
| 1 BTU | 1.055056 kJ |
| 2 BTU | 2.110112 kJ |
| 3 BTU | 3.165168 kJ |
| 4 BTU | 4.220223 kJ |
| 5 BTU | 5.275279 kJ |
| 6 BTU | 6.330335 kJ |
| 7 BTU | 7.385391 kJ |
| 8 BTU | 8.440447 kJ |
| 9 BTU | 9.495503 kJ |
| 10 BTU | 10.550559 kJ |
| 12 BTU | 12.66067 kJ |
| 15 BTU | 15.825838 kJ |
| 20 BTU | 21.101117 kJ |
| 25 BTU | 26.376396 kJ |
| 50 BTU | 52.752793 kJ |
| 100 BTU | 105.505585 kJ |
| 200 BTU | 211.011171 kJ |
| 300 BTU | 316.516756 kJ |
| 500 BTU | 527.527926 kJ |
| 1000 BTU | 1,055.055853 kJ |
| 2000 BTU | 2,110.111705 kJ |
| 5000 BTU | 5,275.279263 kJ |
| 10000 BTU | 10,550.558526 kJ |
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 kilojoule?
A thousand joules. Food energy outside the US is labelled here, alongside or instead of calories.
How many kilojoules are in a British thermal unit?
One British thermal unit is 1.0550559 kilojoules. Going the other way, one kilojoule is 0.94781712 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 kilojoules are in a British thermal unit?
- 1.0550559. A thousand joules. Food energy outside the US is labelled here, alongside or instead of calories.
- How do I convert kilojoules back to British thermal units?
- Divide by 1.0550559, or multiply by 0.94781712 — they are the same operation.
Other energy conversions
Kilojoules to British thermal units — the same conversion the other way.