Calculate gallons per minute quickly using volume and time, or estimate water flow from pipe diameter and velocity. This tool is useful for irrigation, plumbing, pumps, tanks, hoses, drainage, and general water-flow planning.
Get GPM plus LPM, GPH, and cubic feet per second in one clean result panel.
Enter your values and press calculate to see the flow rate in gallons per minute.
Use GPM to estimate sprinkler, drip system, pump, and hose flow requirements.
Check how much water moves through a line, fixture, tank, or supply connection.
Compare pump capacity, water delivery speed, and system performance in one place.
A GPM calculator measures flow rate in gallons per minute. In simple words, it tells you how many gallons of liquid pass through a pipe, hose, pump, tank outlet, or water system every minute.
This calculator supports two common methods. The first method uses total volume and time. The second method estimates flow using pipe diameter and water velocity. That makes it useful for homeowners, plumbers, irrigation installers, pool owners, pump buyers, and maintenance teams.
GPM means gallons per minute. It is a flow rate measurement that shows how many gallons of liquid move through a system in one minute.
Fill a container with a known gallon amount and record the time. Then divide gallons by minutes. For example, 20 gallons filled in 2 minutes equals 10 GPM.
Many homes need enough flow for showers, faucets, toilets, washing machines, and outdoor use. The right GPM depends on household size, fixtures, pipe size, and water pressure.
Yes. The pipe flow mode estimates GPM using inside pipe diameter and water velocity. It is helpful for quick planning, but real systems can vary due to friction loss, fittings, pressure, and pipe material.
No. GPM measures flow rate, while water pressure measures force. A system can have high pressure but limited flow if the pipe, valve, or fixture restricts water movement.