Flow Rate Converter — L/min, m³/h and GPM
Convert flow rates between litres per minute, litres per second, m³/h, US and UK gallons per minute and CFM — with the exact factors.
About this tool
Enter a flow rate, choose the unit you have and the unit you want. You get the exact conversion, how many litres that is per hour and per day, and the same flow in every unit at once — handy for pumps, taps and showers, pools, irrigation, heating and ventilation. 1 L/min = 0.06 m³/h, 1 US gallon = 3.785411784 L and 1 UK gallon = 4.54609 L.
Frequently asked questions
Multiply by 0.06, because one cubic metre is 1,000 litres and an hour has 60 minutes: L/min × 60 ÷ 1,000. So 20 L/min = 1.2 m³/h and 150 L/min = 9 m³/h. To go back, multiply m³/h by 16.667: 3 m³/h = 50 L/min.
Divide by 3.785411784 for US gallons per minute, or by 4.54609 for UK (imperial) gallons per minute. So 20 L/min = 5.28 US gpm = 4.40 UK gpm. Check which gallon a pump or shower head uses: US products use the US gallon, which is about 17 % smaller than the UK one.
Cubic feet per minute, a flow unit used mainly for air: fans, extractor hoods, compressors and ventilation. One cubic foot is exactly 0.3048³ m³ = 28.316846592 litres, so 1 CFM = 28.32 L/min = 1.699 m³/h. A fan rated at 100 CFM moves about 170 m³ of air per hour.
Divide the volume by the flow rate in the same units. A 10,000-litre pool filled at 20 L/min takes 10,000 ÷ 20 = 500 minutes, about 8 hours 20 minutes. A 200-litre water butt at 12 L/min takes about 17 minutes. Measure your own flow by timing how long a bucket of known size takes to fill.
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