Joules to BTU
Convert joules to btu instantly. 1 J = 0.0009478171 BTU. Includes the exact factor, a conversion table of common values and the definition of both units.
How to convert joules to btu
To convert joules to btu, divide by 1055.05585262 (multiply by 0.0009478171). The relationship is fixed, so the same factor works for any quantity — there is nothing to look up and nothing that changes with temperature, location or context.
BTU = J × 0.0009478171
Joules to BTU conversion table
The values people look up most often, rounded for reading. Use the calculator above for anything in between.
| Joules | BTU |
|---|---|
| 1 J | 0.0009478 BTU |
| 2 J | 0.001896 BTU |
| 3 J | 0.002843 BTU |
| 5 J | 0.004739 BTU |
| 10 J | 0.009478 BTU |
| 20 J | 0.018956 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 |
What is a joule?
The SI unit of energy: one newton-metre, or one watt for one second.
What is a btu?
British thermal unit, used for heating and air-conditioning capacity.
The formula
BTU = J × 0.0009478171
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Joules to BTU
- Type the number of joules you want to convert.
- Read the result in btu straight away — there is no button to press.
- Check the table below for the values that come up most often, or reverse the conversion with the linked btu to joules page.
Joules to BTU — frequently asked questions
How many btu are in a joule?
One joule equals 0.0009478171 BTU. BTU = J × 0.0009478171
What is the formula to convert joules to btu?
The formula is BTU = J × 0.0009478171. It is an exact definition rather than an approximation, so the conversion never drifts no matter how large the number.
How do I convert btu back to joules?
Divide instead of multiplying: one btu is 1055.05585262 J. The reverse converter is linked in the related tools list.
Is this conversion exact?
Yes. Both units are defined against the same base unit by international agreement, so the factor is exact — any rounding you see is only in the display, which you can widen by entering more decimal places.
Is this joules to btu free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
What people search for
This page answers each of these searches. They are the exact phrases visitors use to find the joules to btu.
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 19, 2026 · Calculation runs client-side · No data collected · Report an error