Convert Kilojoules to BTU
Kilojoules to BTU is the conversion you need when an energy figure is in metric kJ but you work with the British thermal units used for heating, cooling, and appliance ratings. One kilojoule is approximately 0.9478171203133172 BTU, so the two numbers stay fairly close.
Kilojoules to British thermal units conversion table
| Kilojoules (kJ) | British thermal units (BTU) |
|---|---|
| 1 | 0.947817 |
| 2 | 1.895634 |
| 3 | 2.843451 |
| 5 | 4.739086 |
| 10 | 9.478171 |
| 20 | 18.956342 |
| 50 | 47.390856 |
| 100 | 94.781712 |
| 500 | 473.90856 |
| 1,000 | 947.81712 |
The formula
To convert kilojoules to BTU, multiply the number of kilojoules by 0.9478171203133172:
BTU = kilojoules × 0.9478171203133172
A worked example
Say you have 100 kJ and want it in BTU:
100 × 0.9478171203133172 = 94.781712 BTU
So 100 kilojoules is about 94.78 BTU.
Why it's an approximation
The factor 0.9478171203133172 is a rounded value. The BTU here is the International Table BTU, the standard used for heating and cooling gear, and it's defined from a different measurement system than the joule. Because the two units don't divide evenly, the factor rounds to roughly 0.947817. More decimal places give you more precision if you need it.
When you'll use it
Matching an energy figure given in kilojoules to the BTU ratings on furnaces, air conditioners, and water heaters, comparing appliance specs across metric and imperial data sheets, or working out heating and cooling loads that mix the two units.
Frequently asked questions
How many BTU are in a kilojoule?
About 0.9478171203133172 BTU — roughly 0.947817. It's a rounded figure, so a kilojoule and a BTU are close but not the same size.
Which BTU does this use?
The International Table BTU, which is the standard one for heating and cooling equipment. That's where the factor of approximately 0.9478171203133172 comes from.
Is the kilojoules to BTU conversion exact?
No. The factor is approximately 0.9478171203133172, rounded for everyday use, because the BTU and the joule are defined from different measurement systems that don't divide evenly.