Therms to kWh Converter
Convert therms to kilowatt-hours — the conversion behind a UK or US gas bill. Results update as you type; exact factors shown.
One therm (US) is 29.3071 kilowatt-hours — see the exact factor, not a rounded rule of thumb.
How the therms to kwh converter works
Energy converts through the joule. A thermochemical calorie is exactly 4.184 J, so a food Calorie (kcal) is 4.184 kJ. A kilowatt-hour is exactly 3.6 MJ. A BTU is 1,055.056 J and a US therm is 100,000 BTU.
The UK is metric for most trade and science but keeps miles, pints, stone and mpg (with the imperial gallon) in daily life.
Common energy conversions
| From | To | Units |
|---|---|---|
| 0.1 thm | 2.9307 kWh | therm (US) to kilowatt-hours |
| 0.5 thm | 14.6536 kWh | therm (US) to kilowatt-hours |
| 1 thm | 29.3071 kWh | therm (US) to kilowatt-hours |
| 2 thm | 58.6142 kWh | therm (US) to kilowatt-hours |
| 5 thm | 146.5355 kWh | therm (US) to kilowatt-hours |
| 10 thm | 293.0711 kWh | therm (US) to kilowatt-hours |
| 20 thm | 586.1421 kWh | therm (US) to kilowatt-hours |
| 50 thm | 1,465.3554 kWh | therm (US) to kilowatt-hours |
| 100 thm | 2,930.7107 kWh | therm (US) to kilowatt-hours |
| 200 thm | 5,861.4214 kWh | therm (US) to kilowatt-hours |
| 500 thm | 14,653.5535 kWh | therm (US) to kilowatt-hours |
| 1,000 thm | 29,307.107 kWh | therm (US) to kilowatt-hours |
Units in this converter and their exact factors
| Unit | Symbol | One unit in joules |
|---|---|---|
| joule | J | 1 joule |
| kilojoule | kJ | 1,000 joule |
| megajoule | MJ | 1,000,000 joule |
| calorie (thermochemical) | cal | 4.184 joule |
| kilocalorie (food Calorie) | kcal | 4,184 joule |
| watt-hour | Wh | 3,600 joule |
| kilowatt-hour | kWh | 3,600,000 joule |
| British thermal unit | BTU | 1,055.05585262 joule |
| therm (US) | thm | 105,505,585.262 joule |
| foot-pound | ft·lb | 1.3558179483 joule |
FAQFrequently asked questions about energy conversion
How many kWh in a therm?
29.31 kWh.
What is a therm?
100,000 British thermal units — the traditional gas billing unit in the UK and US.
Why does my gas bill show both?
UK bills measure gas volume, convert to kWh for the charge, and some still show therms alongside.
What is 10 therms?
293.1 kWh.
Is gas cheaper than electricity per kWh?
Usually substantially, which is why the comparison is worth making in the same unit.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Physical Laboratory (NPL) — United Kingdom's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.