Convert Foot-pounds to Therms
1 foot-pound (ft·lbf) equals 1.285374295 × 10⁻⁸ therms (thm).
1 ft·lbf = 1.285374295e-8 thm
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk foot-pound to therm converter to paste a column from Excel.
How to Convert Foot-pound to Therm
- 1 ft·lbf = 1.285374295 × 10⁻⁸ thm
- 1 thm = 77798350.53 ft·lbf
- Example: convert 15 ft·lbf to thm: 15 ft·lbf = 15 × 1.285374295 × 10⁻⁸ thm = 1.928061443 × 10⁻⁷ 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 = ft·lbf × 1.285374295444 × 10⁻⁸
or thm = ft·lbf ÷ 77798350.53063
Derivation from SI units:
- 1 ft·lbf = 0.3048 m × 4.4482216152605 N = 1.3558179483314 J
- 1 thm (US) = 1.054804 × 10⁸ J (NIST SP 811)
- 1 ft·lbf = 1.355817948331 J ÷ 105480400 J per thm = 1.285374295444 × 10⁻⁸ thm
Both units are defined exactly, so the factor is exact. Foot-pound definition: foot-pound; Therm definition: therm.
Worked examples
- A reading of 25 ft·lbf converts to 3.213435739 × 10⁻⁷ thm.
25 ft·lbf × 1.285374295 × 10⁻⁸ = 3.213435739 × 10⁻⁷ thm - A value of 250 ft·lbf is 0.000003213435739 thm.
250 ft·lbf × 1.285374295 × 10⁻⁸ = 0.000003213435739 thm
Foot-pound to Therm conversion table
| Foot-pounds (ft·lbf) | Therms (thm) |
|---|---|
| 1 ft·lbf | 1.285374295 × 10⁻⁸ thm |
| 5 ft·lbf | 6.426871477 × 10⁻⁸ thm |
| 10 ft·lbf | 1.285374295 × 10⁻⁷ thm |
| 25 ft·lbf | 3.213435739 × 10⁻⁷ thm |
| 50 ft·lbf | 6.426871477 × 10⁻⁷ thm |
| 100 ft·lbf | 0.000001285374295 thm |
| 250 ft·lbf | 0.000003213435739 thm |
| 500 ft·lbf | 0.000006426871477 thm |
| 1000 ft·lbf | 0.00001285374295 thm |
| 2000 ft·lbf | 0.00002570748591 thm |
Where it's used
Foot-pounds are used for muzzle energy of firearms and air rifles, while therms appear in US and UK natural-gas bills. Both measure energy, work and heat, so the conversion is a fixed factor.
Foot-pound to other energy units
| Conversion | 1 ft·lbf equals |
|---|---|
| foot-pound to joule | 1.355817948 J |
| foot-pound to kilojoule | 0.001355817948 kJ |
| foot-pound to megajoule | 0.000001355817948 MJ |
| foot-pound to calorie | 0.3240482668 cal |
| foot-pound to kilocalorie | 0.0003240482668 kcal |
| foot-pound to watt-hour | 0.0003766160968 Wh |
| foot-pound to kilowatt-hour | 3.766160968 × 10⁻⁷ kWh |
| foot-pound to BTU | 0.001285067463 BTU |
| foot-pound to therm | 1.285374295 × 10⁻⁸ thm |
| foot-pound to electronvolt | 8.462350028 × 10¹⁸ eV |
| foot-pound to erg | 13558179.48 erg |
Frequently asked questions
How many therms are in 1 foot-pound?
1 ft·lbf = 1.285374295 × 10⁻⁸ thm.
How do I convert foot-pounds to therms?
Multiply the value in ft·lbf by 1.285374295 × 10⁻⁸, or divide it by 77798350.53. For example, 15 ft·lbf × 1.285374295 × 10⁻⁸ = 1.928061443 × 10⁻⁷ thm.
Is the ft·lbf 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, "foot pound-force (ft·lbf)".
- 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 Foot-pounds to Therms. Retrieved October 17, 2026, from https://scientificconverters.com/energy/foot-pounds-to-therms/
IEEE
Scientific Converters, "Convert Foot-pounds to Therms," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/energy/foot-pounds-to-therms/