Gallons Per Minute Calculator (GPM)

Flow rate measures how much water moves through a pipe or fixture in a given time — a critical value for irrigation systems, plumbing, pumps, and water usage audits. Enter your Volume of Water (in gallons) and the Time to Fill (in seconds) into the Gallons Per Minute Calculator to get your flow rate in GPM. Secondary outputs include Gallons Per Hour (GPH), Liters Per Minute (LPM), and Liters Per Hour (LPH).

gallons

Total volume of water measured

seconds

Time taken to fill the container

Results

Gallons Per Minute (GPM)

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Gallons Per Hour (GPH)

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Liters Per Minute (LPM)

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Liters Per Hour (LPH)

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Frequently Asked Questions

What is GPM?

GPM stands for gallons per minute, which is a unit of volumetric flow rate that measures how many gallons of liquid flow through a given point in one minute. It's commonly used to measure water flow in plumbing, pumps, and irrigation systems.

How to calculate gallons per minute?

To calculate GPM, divide the volume of water in gallons by the time in minutes. If you have time in seconds, divide by 60 first to convert to minutes. The formula is: GPM = Volume (gallons) ÷ Time (minutes).

How many GPM is a shower?

A typical shower uses between 2.5 to 5 GPM. Low-flow showerheads are designed to use 2.5 GPM or less to conserve water, while older showerheads may use up to 5 GPM or more.

How many GPM is a garden hose?

A standard garden hose typically flows at 9-17 GPM depending on water pressure and hose diameter. A 5/8-inch hose usually delivers about 17 GPM at 25 PSI, while a 1/2-inch hose delivers about 9 GPM.

1 GPM equals how many LPM?

1 GPM equals approximately 3.785 liters per minute (LPM). This conversion factor comes from the fact that 1 US gallon equals 3.785 liters.

What's the average GPM for a sink faucet?

A typical bathroom sink faucet flows at 1.5-2.2 GPM, while a kitchen sink faucet usually flows at 2.2 GPM. Modern low-flow faucets are designed to use 1.5 GPM or less to conserve water.

How do I measure GPM at home?

To measure GPM at home, use a container of known volume (like a 1-gallon bucket) and time how long it takes to fill. Then use the formula: GPM = Volume in gallons ÷ Time in minutes. For example, if it takes 30 seconds to fill a 1-gallon container, that's 2 GPM.