Flow Rate Converter
Convert a flow rate between litres per minute, gallons per minute, cubic metres per hour and cfm - handy for pumps, pipes and fans.
About the Flow Rate Converter
This tool converts a volumetric flow rate between cubic metres per second, litres per second, litres per minute, cubic metres per hour, gallons per minute (gpm) and cubic feet per minute (cfm). Flow rate is volume moved per unit time, so it describes pumps, pipes, taps, fans and ventilation.
How to use it
- Enter the value you have into its field, for example a pump rated in litres per minute.
- Read the equivalent in gallons per minute, m3/h or cfm.
- Convert in either direction when a spec uses water units (gpm, lpm) or air units (cfm).
A common task is matching a pump curve in litres per minute to a US figure in gpm, where 1 US gallon per minute equals about 3.785 litres per minute. Air handling and ventilation are usually rated in cfm, and 1 cfm equals about 1.699 cubic metres per hour. One caveat: this converter uses the US gallon, so an imperial-gallon source will read slightly differently. It does not account for pressure or pipe size, only the flow units themselves. Everything runs in your browser and nothing is uploaded.
Frequently asked questions
How do I convert gallons per minute to litres per minute?
Multiply US gallons per minute by 3.785. So 10 gpm equals about 37.85 litres per minute.
How many cubic metres per hour is 1 cfm?
One cubic foot per minute equals about 1.699 cubic metres per hour, since a cubic foot is about 0.0283 m3 and there are 60 minutes in an hour.
Does this use US or imperial gallons?
It uses the US gallon (about 3.785 litres). An imperial gallon is about 4.546 litres, so figures from UK sources will differ slightly.
How do I convert litres per second to litres per minute?
Multiply litres per second by 60. So 2 L/s equals 120 litres per minute, because there are 60 seconds in a minute.