The therm here is 100,000 BTU (International Table definition), or exactly 1.05505585262 × 10⁸ joules — derived from the IT BTU value published in NIST Special Publication 811. It is labeled 'therm (US)' after the US definition (EIA: 1 therm = 100,000 Btu). DESNZ's 2025 conversion tables give a matching derived figure: 1 therm = 0.105506 GJ = 29.30711 kWh, and describe the UK/EC therm through the same 100,000-Btu chain. A therm quoted from a source that pins a different flavour of BTU can differ slightly, so the chain used is stated here rather than left to the name.
Definition
- Dimension
- Energy
- Symbols
- therm
- System
- convention
- Base factor
- ×105505585.262
- Exactness
- standard definition
Fixed by a published standard or convention (toe, therm, IT cal/BTU).
Also known as
US thermthermstherm
Sources
Common conversions
for 1 therm| joule | 105,505,585.262 | J | standard definition |
| kilojoule | 105,505.585262 | kJ | standard definition |
| megajoule | 105.505585262 | MJ | standard definition |
| gigajoule | 0.105505585262 | GJ | standard definition |
| kilowatt hour | ~29.3071 | kWh | standard definition |
| megawatt hour | ~0.0293071 | MWh | standard definition |
| British thermal unit | 100,000 | BTU | standard definition |
| million British thermal units | 0.1 | MMBTU | standard definition |
| tonne of oil equivalent | ~0.00251996 | toe | standard definition |