How many CFM is 1 GPM?

1 US gallon per minute equals approximately 0.133681 cubic feet per minute. This follows from 1 US gallon = 231 cubic inches = 0.133681 cubic feet.

How many GPM is 1 CFM?

1 cubic foot per minute equals approximately 7.48052 US gallons per minute. Divide any CFM value by 0.133681 (or multiply by 7.48052) to get GPM.

Does this use US gallons or UK gallons?

This converter uses US liquid gallons (231 in³ per gallon). The UK (imperial) gallon is larger — about 1.20095 US gallons — so results differ. Specify which gallon your source uses.

Is the conversion exact?

The US gallon is defined as exactly 231 cubic inches, and 1 foot = 12 inches, so 1 ft³ = 1,728 in³. The exact factor is 231/1728 ≈ 0.133680556. This tool uses 0.133681 (6 sig figs), which is accurate to within 1 ppm.

Why convert GPM to CFM?

GPM is common for liquid pump specs; CFM is the standard for gas and air flow. Engineers often need to cross-check or combine systems — for example, comparing a water pump discharge rate to a ventilation duct capacity — requiring the same unit system.

GPM to CFM Converter

Name: GPM to CFM Converter
Availability: InStock
Author: Nham Vu

Enter a flow rate in US gallons per minute (GPM) and instantly get the equivalent in cubic feet per minute (CFM).

Enter Flow Rate

Gallons per Minute (GPM)

Result in Cubic Feet per Minute (CFM)

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Conversion: 1 US GPM = 0.133681 CFM | 1 CFM = 7.48052 GPM

Common Flow Rates

GPM	CFM	Application
1	0.1337	Household faucet
2.5	0.3342	Low-flow showerhead
7.48	1.0000	1 CFM equivalent
10	1.337	Small irrigation pump
50	6.684	Residential fire sprinkler
100	13.37	Medium HVAC chiller loop
500	66.84	Commercial cooling system

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Summary

Enter a flow rate in US gallons per minute (GPM) and instantly get the equivalent in cubic feet per minute (CFM).

How it works

Enter the flow rate in US gallons per minute in the input field.
The converter multiplies your value by 0.133681 to get cubic feet per minute.
The result and formula update instantly as you type.
Click Copy to copy the CFM value to your clipboard.
Refer to the table for common real-world flow rates in both units.

Use cases

Size HVAC ductwork by converting pump GPM specs to CFM airflow equivalents.
Translate pump data sheets between GPM and CFM for plumbing design.
Check irrigation system flow rates against pipe capacity specs in CFM.
Convert fire suppression system flow rates for engineering calculations.
Compare water turbine flow data reported in different unit systems.
Verify industrial coolant flow specs between metric and imperial datasheets.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu