Joules to BTU
Convert joules (J) to btu (BTU). Both measure work and power, and the conversion comes up in nutrition, electricity, fitness work.
The Formula
``
btu = joules × 0.000947817120313
joules = btu × 1055.05585262
`
One joule is 9.4782e-4 btu, and one BTU is 1,055.06 joules.
Conversion Table
| Joules | BTU |
|---|---|
| 1 J | 9.4782e-4 BTU |
| 2 J | 0.001896 BTU |
| 5 J | 0.004739 BTU |
| 10 J | 0.009478 BTU |
| 25 J | 0.023695 BTU |
| 50 J | 0.047391 BTU |
| 100 J | 0.094782 BTU |
| 500 J | 0.473909 BTU |
| 1,000 J | 0.947817 BTU |
The Other Direction
| BTU | Joules |
|---|---|
| 1 BTU | 1,055.06 J |
| 2 BTU | 2,110.11 J |
| 5 BTU | 5,275.28 J |
| 10 BTU | 10,550.56 J |
| 25 BTU | 26,376.4 J |
| 50 BTU | 52,752.79 J |
| 100 BTU | 105,505.59 J |
| 500 BTU | 527,527.93 J |
| 1,000 BTU | 1,055,055.85 J |
What Each Unit Is
Joules (J) — the work done by one newton acting over one metre — the SI derived unit of energy. Named for James Prescott Joule, who established the mechanical equivalent of heat.
BTU (BTU) — the energy to raise one pound of water by one degree Fahrenheit, or 1,055 joules. The imperial thermal unit, still standard for US heating, cooling and gas.
A Sense of Scale
Lifting an apple one metre takes about 1 J- A heartbeat uses roughly 1 J
- A window air conditioner is 5,000–12,000 BTU/h
- US furnaces are rated in BTU
Precision
The factor 0.000947817120313 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.
In Code
`javascript
const jouleToBtu = (value) => value * 0.000947817120313;
``
Where This Conversion Comes Up
- Nutrition
- Electricity
- Fitness
- Heating
- Fuel
How Many Decimals Do You Need?
Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 J with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 J becomes | Error |
|---|---|---|---|
| 0 | 0 | 0 | 100.0000% |
| 1 | 0 | 0 | 100.0000% |
| 2 | 0 | 0 | 100.0000% |
| 3 | 0.001 | 0.137 | 5.5056% |
| 4 | 0.0009 | 0.1233 | 5.0450% |
The right number of significant figures is set by your input, not by the converter. If you measured joules to three significant figures, the answer in btu is only good to three — writing more digits claims precision the measurement never had.