Flow Rate Converter
Convert flow rates between gallons per minute (GPM), liters per minute (LPM), m³/h, and cubic feet per minute (CFM).
Used for plumbing, HVAC, and fluid systems.
Type in any field — the others update instantly.
Flow rate is how much fluid moves past a point in a given time. This converter works in volume per time, with liters per minute (LPM) as the base, covering the units you meet around the house and across engineering.
Key relationships:
1 GPM = 3.78541 LPM1 m³/h = 16.6667 LPM1 CFM = 28.3168 LPM
Everyday flow rates:
- A kitchen faucet: about 2.2 GPM (8.3 LPM)
- A shower head: about 2.5 GPM (9.5 LPM)
- A garden hose: 5–10 GPM
- A fire hydrant: 500–1,500 GPM
GPM (gallons per minute) and LPM rule water and plumbing. CFM (cubic feet per minute) is the air-world unit, used for HVAC airflow, ventilation sizing, and air-compressor ratings. They all describe the same idea in different volumes.
Two cautions. First, the US gallon and the UK (Imperial) gallon are different sizes, so a “GPM” figure means about 20 percent more flow in Britain than in America, which matters when reading specs across the Atlantic. Second, for gases, volumetric flow shifts with pressure and temperature because gas compresses. That’s why compressor ratings often quote “standard” CFM (SCFM), measured at a fixed reference condition, so two machines can actually be compared on equal terms.
How we build and check this converter
This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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