Flow Rate Converter Free Online
Convert volumetric flow rate between L/s, L/min, m³/h, m³/s, US gallons per minute (GPM), UK GPM, cubic feet per minute (CFM), and ft³/s. SI base is m³/s.
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Flow Rate Converter Features
HVAC & Plumbing
CFM for ducts, GPM for pumps and faucets, L/min for showers and faucets in metric markets, m³/h for industrial flow.
US & UK Gallons
Includes both US (3.785 L) and UK / imperial (4.546 L) gallons. UK GPM is 20% larger than US GPM.
9 Units
From L/h (drip irrigation) to ft³/s (river hydrology and industrial process). All SI/metric/imperial covered.
Live Conversion
Type a value, see all units instantly.
Swap Units
Quick reverse with the swap button.
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Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Full flow rate conversion | ||
| Live conversion | ||
| All-units result panel | ||
| Bulk CSV / Excel conversion | — | |
| REST API access | — | |
| Custom precision settings | — |
Frequently Asked Questions
Multiply US GPM by 3.785. So 10 US GPM = 37.85 L/min. UK GPM × 4.546 = L/min, so 10 UK GPM = 45.46 L/min.
Modern low-flow showerheads: 7.6 L/min (2.0 US GPM) — the US Energy Policy Act standard. Older heads: 9.5 L/min (2.5 GPM). Pre-1992 heads were ~22 L/min.
Cubic feet per minute. Used for HVAC ducts, exhaust fans, air compressors. A typical bathroom exhaust fan = 50–100 CFM. A whole-home AC system = 400 CFM per ton.
No. US gallon = 3.78541 L. UK (imperial) gallon = 4.54609 L. The UK gallon is ~20% larger. UK GPM = 1.20095 × US GPM.
Modern faucets in the US are limited to 8.3 L/min (2.2 GPM). EU tends toward 6 L/min for water-saving. Older taps can exceed 15 L/min.