Flow Rate Converter
Flow rate measures how much fluid moves past a point in a given amount of time, expressed as a volume divided by a duration. Whenever you describe a pump, a tap, an air vent, or a river, you are talking about flow rate: liters per second, gallons per minute, cubic meters per hour, and so on. The larger the volume moved or the shorter the time, the higher the flow rate.
All Flow Rate Conversions
Showing 100 of 1332 conversions. Use the converter above to access any unit pair.
People convert flow rate constantly because equipment specifications, plumbing codes, and engineering data rarely use the same units. A pump rated in gallons per minute may need to be matched against a pipe sized in liters per second, or an HVAC fan rated in cubic feet per minute (CFM) compared to a duct calculation in cubic meters per hour. Converting correctly keeps systems sized, balanced, and safe.
Flow Rate Units Explained
Metric units combine the liter or the cubic meter with a time unit. Common ones are liters per second (l/s), liters per minute (l/min), liters per hour (l/h), cubic meters per second (m3/s), and cubic meters per hour (m3/h). Since 1 cubic meter equals 1000 liters, these scale cleanly: 1 m3/s = 1000 l/s and 1 m3/h = 1000 l/h. Imperial and US customary units include gallons per minute (gal/min, or GPM), cubic feet per minute (ft3/min, or CFM, the standard for airflow), and cubic feet per second (ft3/s). Important: this tool uses the US gallon (3.785411784 liters), which is smaller than the imperial gallon (4.54609 liters).
How to Convert Flow Rate Units
Convert flow rate by routing through a common base unit, here liters per second (l/s). Each unit has a fixed factor to l/s; divide by one factor and multiply by another. Useful factors: 1 l/min = 1/60 l/s, 1 l/h = 1/3600 l/s, 1 m3/s = 1000 l/s, 1 m3/h = 1/3.6 l/s, 1 US gal/min = 0.0630902 l/s, and 1 ft3/min (CFM) = 0.4719474 l/s. Example: convert 50 US gal/min to m3/h. First to l/s: 50 x 0.0630902 = 3.15451 l/s. Then l/s to m3/h, multiply by 3.6: 3.15451 x 3.6 = 11.356 m3/h. Equivalently, 1 US gal/min = 0.227125 m3/h, so 50 x 0.227125 = 11.356 m3/h.
Common Uses
- Sizing water pumps and matching them to pipe diameters
- Specifying HVAC fans and ventilation in CFM or m3/h
- Reading flow meters for irrigation and sprinkler systems
- Comparing shower, faucet, and appliance flow ratings
- Estimating river or stream discharge for hydrology
- Calibrating industrial process and dosing pumps
- Checking fuel or coolant delivery rates in engines
Accuracy Tips
Always confirm whether a gallon is US or imperial; the imperial gallon is about 20 percent larger, so mixing them throws results off badly. CFM almost always means cubic feet per minute, not per second. Watch the time unit: per second, per minute, and per hour differ by factors of 60 and 3600. For air, note that flow can be quoted at actual (ACFM) or standard (SCFM) conditions, which depend on temperature and pressure.
Frequently Asked Questions
How many liters per minute are in 1 cubic meter per hour?
1 cubic meter per hour equals about 16.667 liters per minute, because 1 m3 = 1000 liters and there are 60 minutes in an hour (1000 / 60 = 16.6667).
How do I convert GPM to liters per minute?
Multiply US gallons per minute by 3.785411784 to get liters per minute. For example, 10 US GPM = 37.854 L/min. If your figure is in imperial gallons, multiply by 4.54609 instead.
What is 1 CFM in cubic meters per hour?
1 cubic foot per minute equals about 1.69901 cubic meters per hour, since 1 cubic foot = 28.316846592 liters and there are 60 minutes per hour (28.316846592 x 60 / 1000).
How many GPM is 1 liter per second?
1 liter per second equals about 15.850 US gallons per minute. Conversely, 1 US GPM is about 0.0630902 liters per second.
Is the gallon in this converter US or imperial?
It uses the US gallon, which is 3.785411784 liters. The imperial (UK) gallon is larger at 4.54609 liters, so a flow in imperial gallons per minute is about 20 percent greater than the same number in US gallons per minute.