Convert Watt-hours to Therms
1 watt-hour (Wh) equals 0.00003412956341 therms (thm).
1 Wh = 0.00003412956341 thm
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk watt-hour to therm converter to paste a column from Excel.
How to Convert Watt-hour to Therm
- 1 Wh = 0.00003412956341 thm
- 1 thm = 29300.11111 Wh
- Example: convert 15 Wh to thm: 15 Wh = 15 × 0.00003412956341 thm = 0.0005119434511 thm
Reference conditions. thm: US therm, 100 000 BTU (59 °F), 105.4804 MJ as given by NIST SP 811. The EC therm is 105.506 MJ.
Formula
thm = Wh × 0.00003412956340704
or thm = Wh ÷ 29300.11111111
Derivation from SI units:
- 1 Wh = 1 W × 3600 s = 3600 J
- 1 thm (US) = 1.054804 × 10⁸ J (NIST SP 811)
- 1 Wh = 3600 J ÷ 105480400 J per thm = 0.00003412956340704 thm
Both units are defined exactly, so the factor is exact. Watt-hour definition: watt-hour; Therm definition: therm.
Worked examples
- A reading of 20 Wh converts to 0.0006825912681 thm.
20 Wh × 0.00003412956341 = 0.0006825912681 thm - A value of 100 Wh is 0.003412956341 thm.
100 Wh × 0.00003412956341 = 0.003412956341 thm
Watt-hour to Therm conversion table
| Watt-hours (Wh) | Therms (thm) |
|---|---|
| 1 Wh | 0.00003412956341 thm |
| 5 Wh | 0.000170647817 thm |
| 10 Wh | 0.0003412956341 thm |
| 15 Wh | 0.0005119434511 thm |
| 20 Wh | 0.0006825912681 thm |
| 50 Wh | 0.00170647817 thm |
| 60 Wh | 0.002047773804 thm |
| 75 Wh | 0.002559717256 thm |
| 100 Wh | 0.003412956341 thm |
| 160 Wh | 0.005460730145 thm |
| 500 Wh | 0.0170647817 thm |
| 1000 Wh | 0.03412956341 thm |
Where it's used
Watt-hours are used for battery capacity (phone ≈ 15 Wh; airline limit 100 Wh per power bank), while therms appear in US and UK natural-gas bills. Both measure energy, work and heat, so the conversion is a fixed factor.
Watt-hour to other energy units
| Conversion | 1 Wh equals |
|---|---|
| watt-hour to joule | 3600 J |
| watt-hour to kilojoule | 3.6 kJ |
| watt-hour to megajoule | 0.0036 MJ |
| watt-hour to calorie | 860.4206501 cal |
| watt-hour to kilocalorie | 0.8604206501 kcal |
| watt-hour to kilowatt-hour | 0.001 kWh |
| watt-hour to BTU | 3.412141633 BTU |
| watt-hour to therm | 0.00003412956341 thm |
| watt-hour to electronvolt | 2.246943267 × 10²² eV |
| watt-hour to foot-pound | 2655.223737 ft·lbf |
| watt-hour to erg | 36000000000 erg |
Frequently asked questions
How many therms are in 1 watt-hour?
1 Wh = 0.00003412956341 thm.
How do I convert watt-hours to therms?
Multiply the value in Wh by 0.00003412956341, or divide it by 29300.11111. For example, 15 Wh × 0.00003412956341 = 0.0005119434511 thm.
Is the Wh to thm conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
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, "watt hour (W·h)".
- 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). Convert Watt-hours to Therms. Retrieved October 17, 2026, from https://scientificconverters.com/energy/watt-hours-to-therms/
IEEE
Scientific Converters, "Convert Watt-hours to Therms," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/watt-hours-to-therms/