Convert British thermal units to kilojoules
Converting British thermal units to kilojoules is a common energy task, whether you are checking a recipe, a spec sheet, a travel distance or a homework problem. Since 1 BTU equals 1.05506 kJ, the math is a single multiplication — and this page does it for you instantly, with the formula, a table of common values and answers to the questions people ask most.
Exact factor
How to convert British thermal units to kilojoules
To convert British thermal units to kilojoules, multiply the number of British thermal units by 1.05506. For example, 10 BTU × 1.05506 = 10.5506 kJ.
kJ = BTU × 1.05506
- Write down the value in British thermal units you want to convert.
- Multiply it by 1.05506 (the exact BTU→kJ factor).
- The result is your value in kilojoules. Check it below with the converter or the table.
Conversion table
Common values of British thermal units and their equivalents in kilojoules:
| BTU | kJ |
|---|---|
| 1 | 1.05506 |
| 2 | 2.11011 |
| 3 | 3.16517 |
| 4 | 4.22022 |
| 5 | 5.27528 |
| 10 | 10.5506 |
| 20 | 21.1011 |
| 25 | 26.3764 |
| 50 | 52.7528 |
| 100 | 105.506 |
| 250 | 263.764 |
| 500 | 527.528 |
About these units
British Thermal Unit (BTU). A British thermal unit is the energy to raise one pound of water by 1 °F, about 1,055 joules. Air conditioners, heaters and grills in the US are rated in BTU.
Kilojoule (kJ). A kilojoule is 1,000 joules, the practical unit for food energy in Australia and Europe and for mechanical work. One kilocalorie equals 4.184 kilojoules.
Frequently asked questions
How do I convert British thermal units to kilojoules?
To convert British thermal units to kilojoules, multiply the number of British thermal units by 1.05506. For example, 10 BTU × 1.05506 = 10.5506 kJ. Or skip the math: type the value into the converter at the top of this page and the result updates instantly.
How many kilojoules are in 1 british thermal unit?
1 BTU = 1.05506 kJ. That is the fixed relationship used by this converter and by international standards.
How many British thermal units are in 1 kilojoule?
1 kJ = 0.947817 BTU. If you are converting in the opposite direction, use our Kilojoule to British Thermal Unit converter for the dedicated table and FAQ.
Is the British thermal units to kilojoules conversion exact?
Yes. Both units are defined by international agreement, so the factor of 1.05506 is exact. Displayed results are rounded to 6 significant digits only for readability.
What is british thermal unit used for?
A British thermal unit is the energy to raise one pound of water by 1 °F, about 1,055 joules. Air conditioners, heaters and grills in the US are rated in BTU.