BTU
The British thermal unit (BTU) is roughly the heat needed to warm one pound of water by 1 °F. The International Table BTU is exactly 1055.05585262 J.
Symbol: BTU
Quantity: energy, work and heat
SI relation: 1 BTU = 1055.05585262 J (exact)
Derivation: 1 BTU_IT = 1055.05585262 J (exact)
Exact: yes, by definition
Reference conditions. International Table BTU (BTU_IT), 1055.05585262 J exactly.
Typical uses
- Furnace, boiler and fuel ratings in the US
- Natural gas (1 therm = 100 000 BTU)
- Air-conditioner capacity in BTU/h
Convert British thermal units to other units
| Conversion | 1 BTU equals | Reverse |
|---|---|---|
| BTU to joule | 1055.055853 J | joule to BTU |
| BTU to kilojoule | 1.055055853 kJ | kilojoule to BTU |
| BTU to kilocalorie | 0.2521644007 kcal | kilocalorie to BTU |
| BTU to kilowatt-hour | 0.0002930710702 kWh | kilowatt-hour to BTU |
| BTU to megajoule | 0.001055055853 MJ | megajoule to BTU |
| BTU to calorie | 252.1644007 cal | calorie to BTU |
| BTU to watt-hour | 0.2930710702 Wh | watt-hour to BTU |
| BTU to therm | 0.00001000238767 thm | therm to BTU |
| BTU to electronvolt | 6.585140678 × 10²¹ eV | electronvolt to BTU |
| BTU to foot-pound | 778.1692623 ft·lbf | foot-pound to BTU |
| BTU to erg | 10550558530 erg | erg to BTU |
Open the Energy Converter to convert any value between all units.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "British thermal unit_IT (Btu_IT)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). BTU. Retrieved October 17, 2026, from https://scientificconverters.com/units/btu/
IEEE
Scientific Converters, "BTU," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/btu/