How many joules are in 1 British thermal unit?

1 British thermal unit equals 1055.06 J.

How do I convert joules back to British thermal units?

Use the reverse converter: 1 joule equals 0.000947817 BTU.

Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.

To convert British thermal units to joules, multiply the value by 1055.05585.

J = BTU × 1055.05585

40 BTU × 1055.05585 = 42202.23 J

British Thermal Unit (BTU): Used for heating, cooling and gas in the US. The IT BTU is about 1,055.056 joules.
Joule (J): The SI unit of energy, one newton-metre, named after James Prescott Joule.

How do I convert British thermal units to joules?: To convert British thermal units to joules, multiply the value by 1055.05585.
How many joules are in 1 British thermal unit?: 1 British thermal unit equals 1055.06 J.
How many joules are in 10 British thermal units?: 10 BTU equals 10550.6 J.
How do I convert joules back to British thermal units?: Use the reverse converter: 1 joule equals 0.000947817 BTU.
Is this converter accurate?: Yes. It uses the exact SI/NIST definitions of each unit and shows up to 6 significant digits.