Gallons Per Minute Calculator (GPM)
Use our gallons per minute calculator to calculate GPM flow rate from volume (US gallons) and time (seconds). Includes the GPM formula, how to figure flow rate, and common GPM conversion tips.
What Is Gallons Per Minute?
Gallons per minute (GPM) is a flow rate that measures how many US gallons of liquid move through a system each minute.
GPM is commonly used for plumbing, pumps, irrigation, filtration, and any situation where you need to understand flow rate capacity.
This calculator takes volume (US gal) and time (sec) and converts it into a flow rate in US gallons per minute.
GPM Formula
Convert seconds to minutes, then divide volume by time in minutes.
There are 60 seconds in a minute.
Equivalent form: GPM = (Volume(gal) × 60) ÷ Time(sec).
Shorter time for the same volume means a higher flow rate.
How to Calculate Gallons Per Minute
- 1
Enter volume in US gallons (gal).
- 2
Enter time in seconds (sec).
- 3
The calculator computes GPM = (Volume × 60) ÷ Time.
Frequently Asked Questions
Use GPM = (Volume in gallons × 60) ÷ Time in seconds. This converts seconds to minutes and gives gal/min.
Flow rate in GPM is how many US gallons of fluid pass a point each minute. It’s a standard way to describe pump and plumbing capacity.
Measure how many gallons you collected (volume) and how many seconds it took (time), then use GPM = (gal × 60) ÷ sec.
It depends on your application (fixtures, irrigation zones, pump sizing, etc.). Once you know the required demand, you can compare it to your measured or rated GPM.
This tool converts a volume-over-time measurement into GPM. If you need unit conversions (like L/min to GPM), you would also need a unit conversion step.