British Thermal Units to Kilojoules Converter
1 British thermal unit ≈ 1.05505585 kilojoules
Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
1 British thermal unit equals 1.05506 kilojoules
How to convert British thermal units to kilojoules
Calories here are thermochemical (4.184 J), while BTU uses the International Table definition. A kilowatt-hour is energy (3.6 MJ), not power; a food Calorie is a kilocalorie.
kJ = BTU × 1.055055853One British thermal unit is 1.055055853 kilojoules, so a single multiplication converts any value.
10.5506 kJ ≈ 10 × 1.055055853Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
British thermal units to kilojoules conversion table
Common values in British thermal units, converted to kilojoules.
| British thermal units (BTU) | Kilojoules (kJ) |
|---|---|
| 1 | 1.0550559 |
| 2 | 2.1101117 |
| 3 | 3.1651676 |
| 4 | 4.2202234 |
| 5 | 5.2752793 |
| 10 | 10.550559 |
| 20 | 21.101117 |
| 25 | 26.376396 |
| 50 | 52.752793 |
| 100 | 105.50559 |
| 250 | 263.76396 |
| 500 | 527.52793 |
| 1,000 | 1,055.0559 |
About these units
British thermal unitBTU
The International Table BTU: 1,055.05585262 joules. The US heating and cooling unit.
Reference: NIST Special Publication 811.
kilojoulekJ
One thousand joules. The metric food-energy unit outside the United States.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.