J to BTU — convert joules to British thermal units
Exact 1 ÷ 1,055.06 = 0.00094781712
1 joule in other units
| Kilojoules | 0.001 | kJ |
|---|---|---|
| Megajoules | 0.000001 | MJ |
| Watt-hours | 0.000277777778 | Wh |
| Kilowatt-hours | 2.7778e-7 | kWh |
| Calories | 0.23900574 | cal |
| Kilocalories | 0.000239005736 | kcal |
| British thermal units | 0.00094781712 | BTU |
| Therms | 9.4782e-9 | thm |
| Foot-pounds | 0.73756215 | ft·lbf |
| Electronvolts | 6,241,509,074,460,763,136 | eV |
J to BTU at a glance
| Joules | British thermal units |
|---|---|
| 1 J | 0.00094781712 BTU |
| 2 J | 0.001895634241 BTU |
| 3 J | 0.002843451361 BTU |
| 5 J | 0.004739085602 BTU |
| 10 J | 0.009478171203 BTU |
| 20 J | 0.01895634 BTU |
| 25 J | 0.02369543 BTU |
| 50 J | 0.04739086 BTU |
| 100 J | 0.09478171 BTU |
| 250 J | 0.23695428 BTU |
| 500 J | 0.47390856 BTU |
| 1,000 J | 0.94781712 BTU |
How to convert joules to British thermal units
Multiply by 0.00094781712 — one joule is 0.00094781712 British thermal units. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 1 ÷ 1,055.06 = 0.00094781712
What these units are
The joule and the British thermal unit are covered in the energy unit guide, along with every other unit on this page.
Questions
How many British thermal units are in a joule?
One joule is 0.00094781712 British thermal units. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 1 joule in British thermal units?
1 joule is 0.00094781712 British thermal units. The working is 1 ÷ 1,055.06 = 0.00094781712.
Is a food Calorie the same as a calorie?
No — it is a thousand of them. The Calorie on a nutrition label is a kilocalorie, written with a capital C in principle and almost never in practice. A 250 Calorie chocolate bar holds 250,000 physics calories, or about 1,046 kilojoules, which is why European labels quote kJ alongside.
What does a kilowatt-hour actually represent?
One kilowatt drawn for one hour — a 1,000 W heater running for sixty minutes, or a 100 W bulb for ten hours. It is the unit your electricity bill is priced in, and it equals exactly 3.6 million joules.
How much energy is one BTU?
Roughly the heat needed to raise one pound of water by one degree Fahrenheit — about 1,055 joules, or the energy in a single kitchen match. Air conditioners are rated in BTU per hour, where a 12,000 BTU/h unit is one "ton" of cooling and draws around 3.5 kW of heat.
Why is the electronvolt so small?
Because it is sized for single particles: it is the energy one electron picks up crossing a one-volt potential difference. At about 1.6 × 10⁻¹⁹ joules it would be absurd for anything larger, which is precisely why particle physics uses it instead of dragging around twenty leading zeros.