Energy converter
Kilojoules to British Thermal Units
If you need to know how many British Thermal Units one Kilojoules contains, the answer is 0.94781712. The conversion is linear, so 10 kJ is 9.478171 BTU and 100 kJ is 94.781712 BTU. Use the converter for any other value.
Formula 1 kJ = 0.94781712 BTU
Need the other direction? British Thermal Units to Kilojoules.
How to convert Kilojoules to British Thermal Units
A kilojoule is 1,000 joules and appears on nutrition labels in many countries. The international table BTU is about 1,055.06 joules, used in heating and cooling.
To convert Kilojoules to British Thermal Units, multiply the value in kJ by 0.94781712. For example, 10 kJ × 0.94781712 = 9.478171 BTU. This works because the ratio between the two units is constant for every value in energy.
Worked examples
| kJ | BTU |
|---|---|
| 1 kJ | 0.94781712 BTU |
| 2.5 kJ | 2.369543 BTU |
| 5 kJ | 4.739086 BTU |
| 10 kJ | 9.478171 BTU |
| 25 kJ | 23.695428 BTU |
| 50 kJ | 47.390856 BTU |
| 100 kJ | 94.781712 BTU |
Reverse conversion
| BTU | kJ |
|---|---|
| 1 BTU | 1.055056 kJ |
| 5 BTU | 5.275279 kJ |
| 10 BTU | 10.550559 kJ |
| 25 BTU | 26.376396 kJ |
| 50 BTU | 52.752793 kJ |
| 100 BTU | 105.505585 kJ |
When this conversion is useful
This is the calculation you need when you are comparing a nutrition label, an electricity bill or a heating system. Because the factor is fixed, you can use the same number for a single measurement or for a batch: 1,000 kJ is 947.81712 BTU.
Is the conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Reference: BIPM SI Brochure and NIST SP 811. Last reviewed: 2026-11-01.
kJ to BTU conversion chart
The chart lists the most requested values. For a value that is not here, use the converter at the top of the page.
| Kilojoules (kJ) | British Thermal Units (BTU) |
|---|---|
| 1 kJ | 0.94781712 BTU |
| 2 kJ | 1.895634 BTU |
| 3 kJ | 2.843451 BTU |
| 4 kJ | 3.791268 BTU |
| 5 kJ | 4.739086 BTU |
| 6 kJ | 5.686903 BTU |
| 7 kJ | 6.63472 BTU |
| 8 kJ | 7.582537 BTU |
| 9 kJ | 8.530354 BTU |
| 10 kJ | 9.478171 BTU |
| 11 kJ | 10.425988 BTU |
| 12 kJ | 11.373805 BTU |
| 13 kJ | 12.321623 BTU |
| 14 kJ | 13.26944 BTU |
| 15 kJ | 14.217257 BTU |
| 16 kJ | 15.165074 BTU |
| 17 kJ | 16.112891 BTU |
| 18 kJ | 17.060708 BTU |
| 19 kJ | 18.008525 BTU |
| 20 kJ | 18.956342 BTU |
| 21 kJ | 19.90416 BTU |
| 22 kJ | 20.851977 BTU |
| 23 kJ | 21.799794 BTU |
| 24 kJ | 22.747611 BTU |
| 25 kJ | 23.695428 BTU |
| 26 kJ | 24.643245 BTU |
| 27 kJ | 25.591062 BTU |
| 28 kJ | 26.538879 BTU |
| 29 kJ | 27.486696 BTU |
| 30 kJ | 28.434514 BTU |
| 31 kJ | 29.382331 BTU |
| 32 kJ | 30.330148 BTU |
| 33 kJ | 31.277965 BTU |
| 34 kJ | 32.225782 BTU |
| 35 kJ | 33.173599 BTU |
| 36 kJ | 34.121416 BTU |
| 37 kJ | 35.069233 BTU |
| 38 kJ | 36.017051 BTU |
| 39 kJ | 36.964868 BTU |
| 40 kJ | 37.912685 BTU |
| 41 kJ | 38.860502 BTU |
| 42 kJ | 39.808319 BTU |
| 43 kJ | 40.756136 BTU |
| 44 kJ | 41.703953 BTU |
| 45 kJ | 42.65177 BTU |
| 46 kJ | 43.599588 BTU |
| 47 kJ | 44.547405 BTU |
| 48 kJ | 45.495222 BTU |
| 49 kJ | 46.443039 BTU |
| 50 kJ | 47.390856 BTU |
| 60 kJ | 56.869027 BTU |
| 70 kJ | 66.347198 BTU |
| 80 kJ | 75.82537 BTU |
| 90 kJ | 85.303541 BTU |
| 100 kJ | 94.781712 BTU |
Frequently asked questions
How many British Thermal Units are in 1 Kilojoules?
1 kJ equals 0.94781712 BTU.
How do I convert Kilojoules to British Thermal Units?
Multiply the kJ value by 0.94781712. Example: 25 kJ = 23.695428 BTU.
What is 2.5 kJ in BTU?
2.5 kJ = 2.369543 BTU.
Is the kJ to BTU conversion exact?
Yes for practical use: the factors come from international definitions, with rounding applied only for display.
Does the calculator work offline?
Yes. The conversion runs in your browser with JavaScript, so it works after the page has loaded, even without a connection.