Enter the gallons per minute and the cubic feet per second into the calculator to determine the missing variable.

Gallons Per Minute To Cubic Feet Per Second Calculator

GPM ↔ CFS
Flow ↔ Velocity

Enter any 1 value to calculate the missing variable

Gallons Per Minute To Cubic Feet Per Second Formula

The following formula is used to convert gallons per minute (GPM) to cubic feet per second (CFS).

CFS = GPM * (0.133681 / 60)

Variables:

  • CFS is the cubic feet per second
  • GPM is the gallons per minute
  • 0.133681 is the conversion factor from gallons to cubic feet
  • 60 is the number of seconds in a minute

To convert gallons per minute to cubic feet per second, multiply the GPM by the conversion factor (0.133681) and then divide by 60.

US Gallons per Minute (GPM) to Cubic Feet per Second (CFS) Conversion Table
Gallons per Minute (US GPM) Cubic Feet per Second (CFS)
10.00223
20.00446
50.01114
100.02228
150.03342
200.04456
250.05570
300.06684
400.08912
500.11140
600.13368
750.16710
800.17824
1000.22280
1250.27850
1500.33420
2000.44560
2500.55700
3000.66840
5001.11400
US customary: 1 GPM ≈ 0.002228 CFS; 1 CFS ≈ 448.831 GPM.

What is Gallons Per Minute?

Gallons per minute (GPM) is a unit of flow rate that indicates the number of gallons of liquid that flow out of a system in one minute. It is commonly used in the United States to measure the flow rate of water in plumbing systems, irrigation systems, and other fluid transport systems.

What is Cubic Feet Per Second?

Cubic feet per second (CFS) is a unit of flow rate that indicates the volume of fluid passing a point in a system per second. It is commonly used in hydrology, river engineering, and environmental engineering to measure the flow of water in rivers, streams, and other open channels.

How to Calculate Gallons Per Minute to Cubic Feet Per Second?

The following steps outline how to calculate the conversion from gallons per minute to cubic feet per second.


  1. First, determine the flow rate in gallons per minute (GPM).
  2. Next, multiply the GPM by the conversion factor (0.133681).
  3. Finally, divide the result by 60 to get the flow rate in cubic feet per second (CFS).
  4. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Gallons Per Minute (GPM) = 120

Using the formula, CFS = GPM * (0.133681 / 60), we get:

CFS = 120 * (0.133681 / 60) ≈ 0.267362