Foot-pounds per Second to BTU per Hour (ft-lbf/s to BTU/h)

Formula

BTU/h = ft·lbf/s × 4.626242868444

Derivation from SI units:

• 1 ft·lbf/s = 1.3558179483314 W
• 1 BTU/h = 1055.05585262 J ÷ 3600 s = 0.29307107 W
• 1 ft·lbf/s = 1.355817948331 W ÷ 0.2930710701722 W per BTU/h = 4.626242868444 BTU/h

Both units are defined exactly, so the factor is exact. Foot-pound per Second definition: foot-pound per second; BTU per Hour definition: BTU per hour.

Worked examples

1. A reading of 100 ft·lbf/s converts to 462.6242868 BTU/h.
   100 ft·lbf/s × 4.626242868 = 462.6242868 BTU/h
2. A value of 1000 ft·lbf/s is 4626.242868 BTU/h.
   1000 ft·lbf/s × 4.626242868 = 4626.242868 BTU/h

Where it's used

Foot-pounds per Second are used for mechanics problems in US units, while BTU per hour appear in air-conditioner and heat-pump capacity (e.g. 12 000 BTU/h). Both measure power (energy per unit time), so the conversion is a fixed factor.

Foot-pound per Second to other power units

Frequently asked questions

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 per second".
• 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, "British thermal unit_IT per hour".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.