💧 Flow Rate Converter
Plumbers use gal/min, HVAC uses CFM, industrial uses m³/h. Same concept — volume per time — every trade has its own jargon.
Last updated — conversions use exact ISO unit definitions.
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How it works
Flow rate measures volume per time. All conversions route through cubic meters per second (m³/s). The US and UK use different gallons (US gal = 3.785 L, UK gal = 4.546 L), so gallons-per-minute conversion depends on which country's gallon you mean — this tool handles both.
Common plumbing units: liters per minute (L/min) for faucets, gallons per minute (GPM) for showerheads, and cubic feet per minute (CFM) for airflow in HVAC. 1 CFM ≈ 28.317 L/min, 1 US GPM ≈ 3.785 L/min.
For pumps and industrial flow, you'll see m³/h (cubic meters per hour) and m³/s. 1 m³/s = 3,600 m³/h = 211.9 CFM. The relationship is linear — just multiply or divide by the right factor.
Real-world applications
Plumbing and water supply: Standard showerheads flow 2.0-2.5 GPM (7.6-9.5 L/min). A low-flow model is 1.5 GPM. If you shower for 10 minutes, you use 15-25 gallons (57-95 L).
HVAC airflow: Bathroom exhaust fans are rated in CFM. A 50 CFM fan = 1,416 L/min. Air conditioners move 350-400 CFM per ton of cooling.
How flow rates relate
1 m³ = 1000 L = 35.3 ft³ = 264 US gal. Typical kitchen faucet: 5-6 L/min. Garden hose: 15-25 L/min. 4-inch water main: 500+ L/min.
How accurate are these conversions?
All conversions use ISO 80000 standard unit definitions. For example, 1 inch = 2.54 centimeters exactly by international agreement.
Why can't I see all units on mobile?
The result table scrolls horizontally. The headline pair above shows the most commonly requested conversion.
Do you store my inputs?
No. All calculations happen in your browser. We collect zero personal data.
General information only — see our disclaimer.