BTU to kJ – convert British thermal units to kilojoules
Convert BTU to kilojoules (British thermal units to kJ) to turn imperial heating and cooling figures into SI units for easier engineering and energy analysis.
Open the interactive BTU → kJ converter:
Use main converter (BTU → kJ) or switch to kJ → BTUFrom the homepage you can also convert between BTU, kWh, joules and megajoules in one place.
Quick reference: BTU to kJ
One BTU is about 1.05506 kJ. So: kJ = BTU × 1.05506. Examples:
| Energy (BTU) | Energy (kJ, approx.) |
|---|---|
| 100 BTU | 105.51 kJ |
| 500 BTU | 527.53 kJ |
| 1,000 BTU | 1,055.06 kJ |
| 5,000 BTU | 5,275.3 kJ |
| 10,000 BTU | 10,550.6 kJ |
| 50,000 BTU | 52,753 kJ |
Why convert BTU to kJ?
BTU to kJ is useful when you:
- Compare HVAC equipment rated in BTU with engineering specs in SI units.
- Analyse building energy performance and fuel use internationally.
- Convert manufacturer datasheets into a consistent kilojoule basis.
- Teach energy unit relationships between BTU, kJ, MJ and kWh.
Other energy converters on this site
For quick estimates you might round 1 BTU ≈ 1.06 kJ, but the converter keeps the more precise 1.05506 factor.
Page last updated: 4 December 2025.