About Flow Rate Conversion
Flow rate conversions are essential in plumbing, HVAC, chemical processing, and hydraulics.
Flow rate units
Flow rate is volume per unit of time. One US gallon per minute is 3.785411784 L/min, one cubic foot per minute is 28.316846592 L/min, and one cubic meter per hour is 16.667 L/min. A liter per hour is 1/60 of a liter per minute.
The gallon here is the US gallon. A UK imperial gallon is 4.54609 liters, about 20% larger, so a UK gpm figure is 1.2 times a US one.
Where each unit is used
- GPM: pumps, wells, faucets and showerheads in the US. The federal limit for showerheads is 2.5 gpm, which is 9.46 L/min.
- CFM: airflow through fans, range hoods, HVAC ducts and air compressors.
- m³/h: industrial pumps, ventilation and HVAC in metric countries.
- L/min: pumps, medical oxygen and laboratory equipment.
Air flow at different conditions
Gas volumes change with pressure and temperature. Compressed air is often rated in SCFM, standard cubic feet per minute, which refers to air at standard conditions rather than at the compressor outlet. This converter converts units at the same conditions, so convert SCFM to standard m³/h, not to actual m³/h.