British thermal units to joules
Type a value in British thermal units to see it in joules straight away, or type in the second box to convert back.
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How to use it
- Type the value in the British thermal units box.
- Read the result in joules as you type, and pick the precision you need.
- Swap the direction to convert back, or copy the result.
How it is calculated
J = BTU × 1,055.055853
Multiply the value in British thermal units by 1,055.055853 to get joules.
Example
To convert 25 BTU to joules: 25 × 1,055.055853 = 26,376.4 J.
Conversion table
| British thermal units (BTU) | Joules (J) |
|---|---|
| 1 | 1,055.06 |
| 2 | 2,110.11 |
| 3 | 3,165.17 |
| 5 | 5,275.28 |
| 10 | 10,550.6 |
| 20 | 21,101.1 |
| 25 | 26,376.4 |
| 50 | 52,752.8 |
| 100 | 105,506 |
| 250 | 263,764 |
| 500 | 527,528 |
| 1,000 | 1,055,060 |
About the units
- British thermal unit
- The imperial unit of heat, using the International Table definition of exactly 1055.05585262 joules. Seen in air conditioner and heater ratings.
- Joule
- The SI unit of energy, equal to the work done by a force of one newton moving an object one meter.
Limits and caveats
- Results are rounded for display and computed with the browser's floating point precision (about 15 significant digits).
- Both unit factors are exact by their official definitions.
Questions about this tool
How many joules are in one British thermal unit?
1 BTU = 1,055.06 J exactly.
How do I convert British thermal units to joules?
Use J = BTU × 1,055.055853. For example, 25 BTU = 26,376.4 J.
How many British thermal units are in one joule?
1 J = 0.000947817 BTU.
Which calorie do these converters use?
The thermochemical calorie, exactly 4.184 joules, the factor many countries use to turn kcal into kJ on food labels. The International Table calorie is 4.1868 joules, less than 0.07% larger.
What is the difference between kW and kWh?
A kilowatt is a unit of power, the rate of using energy, while a kilowatt-hour is an amount of energy. A 2 kW heater running for three hours uses 6 kWh.