Kilojoules to BTU
Convert kilojoules (kJ) to btu (BTU). Both measure work and power, and the conversion comes up in nutrition, electricity, fitness work.
The Formula
``
btu = kilojoules × 0.947817120313
kilojoules = btu × 1.05505585262
`
One kilojoule is 0.947817 btu, and one BTU is 1.0551 kilojoules.
Conversion Table
| Kilojoules | BTU |
|---|---|
| 1 kJ | 0.947817 BTU |
| 2 kJ | 1.8956 BTU |
| 5 kJ | 4.7391 BTU |
| 10 kJ | 9.4782 BTU |
| 25 kJ | 23.6954 BTU |
| 50 kJ | 47.3909 BTU |
| 100 kJ | 94.7817 BTU |
| 500 kJ | 473.9086 BTU |
| 1,000 kJ | 947.8171 BTU |
The Other Direction
| BTU | Kilojoules |
|---|---|
| 1 BTU | 1.0551 kJ |
| 2 BTU | 2.1101 kJ |
| 5 BTU | 5.2753 kJ |
| 10 BTU | 10.5506 kJ |
| 25 BTU | 26.3764 kJ |
| 50 BTU | 52.7528 kJ |
| 100 BTU | 105.5056 kJ |
| 500 BTU | 527.5279 kJ |
| 1,000 BTU | 1,055.06 kJ |
What Each Unit Is
Kilojoules (kJ) — 1,000 joules. The metric food-energy unit outside North America.
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
An apple holds about 400 kJ- Daily intake is around 8,700 kJ
- A window air conditioner is 5,000–12,000 BTU/h
- US furnaces are rated in BTU
Doing It in Your Head
Multiply by 18, then divide by 19. That is off by 0.05% — close enough to judge a
distance, a weight or a price, and not close enough to sign off on a drawing.
Exact Mental shortcut 9.4782 BTU 9.4737 BTU 94.7817 BTU 94.7368 BTU
Precision
The factor 0.947817120313 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 kilojouleToBtu = (value) => value * 0.947817120313;
``
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 kJ with the factor truncated at each decimal place:
| Decimals kept | Factor | 137 kJ becomes | Error |
|---|---|---|---|
| 0 | 1 | 137 | 5.5056% |
| 1 | 0.9 | 123.3 | 5.0450% |
| 2 | 0.95 | 130.15 | 0.2303% |
| 3 | 0.948 | 129.876 | 0.0193% |
| 4 | 0.9478 | 129.849 | 0.0018% |
The right number of significant figures is set by your input, not by the converter. If you measured kilojoules to three significant figures, the answer in btu is only good to three — writing more digits claims precision the measurement never had.