British Thermal Units to Joules Converter
1 British thermal unit ≈ 1,055.05585 joules
Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
1 British thermal unit equals 1,055.06 joules
How to convert British thermal units to joules
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.
J = BTU × 1055.055853One British thermal unit is 1055.055853 joules, so a single multiplication converts any value.
10,550.6 J ≈ 10 × 1055.055853Several BTU definitions exist. This converter uses the International Table BTU, the one used by HVAC equipment ratings.
British thermal units to joules conversion table
Common values in British thermal units, converted to joules.
| British thermal units (BTU) | Joules (J) |
|---|---|
| 1 | 1,055.0559 |
| 2 | 2,110.1117 |
| 3 | 3,165.1676 |
| 4 | 4,220.2234 |
| 5 | 5,275.2793 |
| 10 | 10,550.559 |
| 20 | 21,101.117 |
| 25 | 26,376.396 |
| 50 | 52,752.793 |
| 100 | 105,505.59 |
| 250 | 263,763.96 |
| 500 | 527,527.93 |
| 1,000 | 1,055,055.9 |
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.
jouleJ
The SI derived unit of energy: one newton acting through one metre.
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.