To convert btu to megajoules, multiply by 0.001055055853.
The calculation uses 1 BTU = 0.001055055853 MJ. 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
MJ- Output unit: megajoules
How to use this calculator
- Enter a value in BTU.
- Multiply by the stored conversion factor.
- Read the result in MJ; divide by the same factor to convert back.
Worked examples
Worked conversion
1 BTU × 0.001055055853 ≈ 0.001055055853 MJ.
Reverse conversion
0.001055055853 MJ ÷ 0.001055055853 ≈ 1 BTU. Rounding intermediate values can change the last displayed digit.
Frequently asked questions
What factor does this converter use?
It uses 0.001055055853 MJ 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 MJ table
| BTU | MJ (rounded) |
|---|---|
| 0 | 0 |
| 1 | 0.001055055853 |
| 2 | 0.002110111705 |
| 5 | 0.005275279263 |
| 10 | 0.01055055853 |
| 100 | 0.1055055853 |