Btus to Kilojoules
A British Thermal Unit is the energy to raise 1 pound of water by 1°F, used to rate air conditioners and heaters in the US. A kilojoule is 1,000 joules, used on nutrition labels outside the US to state food energy content. 1 BTU equals ≈1.05506 kJ, so converting between them is a matter of multiplying by that fixed factor — type any value into the converter below and both sides update instantly as you type.
Both units belong to energy, measured here against energy's base unit (J) — every other energy unit on this site converts through that same reference point, which is why the table below can also be read as a quick cross-check against nearby values.
Formula
kJ = BTU × ≈1.05506
BTU = kJ × ≈0.947817
Worked example: 5 BTU × ≈1.05506 = ≈5.27528 kJ.
Conversion table
| BTU (BTU) | Kilojoule (kJ) |
|---|---|
| 1 BTU | ≈1.05506 kJ |
| 2 BTU | ≈2.11011 kJ |
| 3 BTU | ≈3.16517 kJ |
| 5 BTU | ≈5.27528 kJ |
| 10 BTU | ≈10.5506 kJ |
| 20 BTU | ≈21.1011 kJ |
| 25 BTU | ≈26.3764 kJ |
| 50 BTU | ≈52.7528 kJ |
| 100 BTU | ≈105.506 kJ |
| 250 BTU | ≈263.764 kJ |
| 500 BTU | ≈527.528 kJ |
| 1,000 BTU | ≈1,055.06 kJ |
Frequently asked
- How many Kilojoules in a btu?
- 1 BTU equals ≈1.05506 kJ.
- How do I convert BTUs to Kilojoules?
- Multiply the value in BTU by ≈1.05506 to get kJ. The converter above does this instantly as you type.
- Is the conversion exact?
- Yes — BTU and Kilojoule are both defined by a fixed conversion factor to energy's base unit (J), so the result shown is exact to the precision displayed, not an approximation.