cubic feet per minute to US gallons per minute

A cubic foot holds exactly 7.4805194805 US gallons — the number every tank and pool calculator uses — so a cubic foot per minute of anything is 7.4805194805 gallons per minute. Compressed air ratings in CFM, cooling tower air flows in CFM, and water flows in GPM all meet at this factor in HVAC and industrial plants, where the same fan moves air that engineers must compare to the water side.

By EnginStack Engineering Team | Verified by engineers, built on NIST metrology standards About →
cubic feet per minute
10 US gallons per minute
10 cubic feet per minute = 74.80519481 US gallons per minute 10 US gallons per minute = 1.33680556 cubic feet per minute

Authority: NIST SP 811 (SI usage guide) and the 1959 International Yard and Pound Agreement. The coefficient above is a defined value — it does not come from measurement and carries no uncertainty.

cubic feet per minute to US gallons per minute

The factor is exact: one cubic foot is 1,728 in³ and one US gallon is 231 in³, so one cubic foot holds 1,728/231 = 7.4805194805 gallons. Per minute, that is the CFM-to-GPM factor. It is the reciprocal of the 0.13368 that goes the other way, and it is the only non-decimal flow constant on this site because it lives entirely inside the inch world — no liter, no meter, just the two inch-volume definitions and a minute.

US gallons per minute = cubic feet per minute × 7.4805194805
1 CFM = 7.4805194805 GPM — 1,728 in³ ÷ 231 in³
The factor is exact from both inch-volume definitions.

Common cubic feet per minute to US gallons per minute Conversions

cubic feet per minuteUS gallons per minuteContext
1 CFM7.48 GPMThe definitional anchor.
10 CFM74.81 GPMA small air compressor's flow.
100 CFM748.1 GPMA cooling tower air stream.
500 CFM3,740 GPMA large AHU air flow.
1,000 CFM7,481 GPMAn industrial fan.

Engineering Context

This is the cubic feet to gallons volume conversion applied per minute, and it inverts the GPM to CFM page. The flow rate hub collects the full family, and air-flow work connects to the pressure hub — a fan's CFM at a given static pressure is the compressor equivalent of a pump's GPM at head.

More: GPM to CFM · CFM to GPM · ft³ to gal · Flow Rate Hub

Related Unit Converters

Gpm To Cfm Cubic Feet To Gallons Pressure Converters Flow Rate Converters

Frequently Asked Questions

How many GPM is 1 CFM?

Exactly 7.4805194805. A cubic foot is 1,728 in³ and a US gallon is 231 in³, so the ratio is exact.

Why is 7.48 such a famous number?

Because it converts cubic feet to US gallons — the anchor of every aquarium, pool, and tank volume calculation in America. 'A cubic foot of water is 7.48 gallons and weighs 62.4 pounds' is a mantra of the trade.

Can I use 7.5 as a shortcut?

Yes, for mental math — 7.5 is within 0.26%. For tank sizing and process balances, use the full 7.4805194805, since the error compounds across large volumes and flows.