Convert Cubic Feet per Minute to Gallons per Minute

Formula

GPM = CFM × 7.480519480519

Derivation from SI units:

• 1 CFM = (0.3048 m)³ ÷ 60 s = 4.719474432 × 10⁻⁴ m³/s
• 1 GPM = 231 in³ ÷ 60 s = 0.003785411784 m³ ÷ 60 s = 6.30901964 × 10⁻⁵ m³/s
• 1 CFM = 0.0004719474432 m³/s ÷ 0.0000630901964 m³/s per GPM = 7.480519480519 GPM

Both units are defined exactly, so the factor is exact. Cubic Foot per Minute definition: cubic foot per minute; Gallon per Minute definition: US gallon per minute.

Worked examples

1. A reading of 100 CFM converts to 748.0519481 GPM.
   100 CFM × 7.480519481 = 748.0519481 GPM
2. A value of 800 CFM is 5984.415584 GPM.
   800 CFM × 7.480519481 = 5984.415584 GPM

Where it's used

Cubic Feet per Minute are used for US HVAC airflow (about 400 CFM per ton of cooling), while US gallons per minute appear in pump, well and irrigation ratings. Both measure volumetric flow rate (volume per unit time), so the conversion is a fixed factor.

Cubic Foot per Minute to other flow rate 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, "cubic foot per minute (ft³/min)".
• 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, "gallon [U.S.] per minute (gpm)".

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