Therm (thm)
The US therm is 100 000 BTU, used to bill natural gas. NIST gives it as 105.4804 MJ, about 29.3 kWh.
Symbol: thm
Quantity: energy, work and heat
SI relation: 1 thm = 105480400 J (exact)
Derivation: 1 thm (US) = 1.054804 × 10⁸ J (NIST SP 811)
Exact: yes, by definition
Reference conditions. US therm, 100 000 BTU (59 °F), 105.4804 MJ as given by NIST SP 811. The EC therm is 105.506 MJ.
Typical uses
- US and UK natural-gas bills
- Comparing gas and electric heating costs
Convert therms to other units
| Conversion | 1 thm equals | Reverse |
|---|---|---|
| therm to joule | 105480400 J | joule to therm |
| therm to kilojoule | 105480.4 kJ | kilojoule to therm |
| therm to kilocalorie | 25210.42065 kcal | kilocalorie to therm |
| therm to kilowatt-hour | 29.30011111 kWh | kilowatt-hour to therm |
| therm to BTU | 99976.12898 BTU | BTU to therm |
| therm to megajoule | 105.4804 MJ | megajoule to therm |
| therm to calorie | 25210420.65 cal | calorie to therm |
| therm to watt-hour | 29300.11111 Wh | watt-hour to therm |
| therm to electronvolt | 6.583568738 × 10²⁶ eV | electronvolt to therm |
| therm to foot-pound | 77798350.53 ft·lbf | foot-pound to therm |
| therm to erg | 1.054804 × 10¹⁵ erg | erg to therm |
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, "therm (U.S.)".
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). Therm (thm). Retrieved October 17, 2026, from https://scientificconverters.com/units/therm/
IEEE
Scientific Converters, "Therm (thm)," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/units/therm/