To convert btu to joules, multiply by 1055.055853.
The calculation uses 1 BTU = 1055.055853 J. Results are displayed to at most 10 significant digits. Definitions can be exact while a displayed decimal is rounded. Match the displayed precision to your original measurement.
Uses the International Table BTU. Other BTU definitions differ slightly.
The formula
BTU- Input unit: btu
J- Output unit: joules
How to use this calculator
- Enter a value in BTU.
- Multiply by the stored conversion factor.
- Read the result in J; divide by the same factor to convert back.
Worked examples
Worked conversion
1 BTU × 1055.055853 ≈ 1055.055853 J.
Reverse conversion
1055.055853 J ÷ 1055.055853 ≈ 1 BTU. Rounding intermediate values can change the last displayed digit.
Frequently asked questions
What factor does this converter use?
It uses 1055.055853 J per BTU. Uses the International Table BTU. Other BTU definitions differ slightly.
Why can another converter show a slightly different answer?
Check the unit convention first (such as US versus Imperial or decimal versus binary), then compare rounding. Measurement uncertainty is separate from the unit conversion.
BTU to J table
| BTU | J (rounded) |
|---|---|
| 0 | 0 |
| 1 | 1055.055853 |
| 2 | 2110.111705 |
| 5 | 5275.279263 |
| 10 | 10550.55853 |
| 100 | 105505.5853 |