Flow Rate Converter
Convert volumetric flow between L/min, GPM, m³/h, and L/s.
Conversion sheet
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Pumps, faucets, HVAC systems, and process equipment all rate flow differently — liters per minute on a European pump, gallons per minute on a US one, and cubic meters per hour on building plans. This converter moves a volumetric flow rate between L/min, L/s, US and UK gallons per minute, m³/h, and cubic feet per minute.
How it works
Every flow rate converts through liters per minute as the base unit.
Every unit is referenced to liters per minute (L/min) as the base. The factors reflect each unit's volume and time span: 1 L/s = 60 L/min, 1 US gallon/min = 3.78541 L/min, 1 UK gallon/min = 4.54609 L/min, 1 m³/h = 16.6667 L/min, and 1 ft³/min = 28.3168 L/min. The converter handles both the volume difference and the per-second-versus-per-minute-versus-per-hour difference in one step.
This is volumetric flow — the volume of fluid moving per unit time — not mass flow or velocity. It tells you how much fluid passes a point, not how fast it travels or how heavy it is, so the same L/min can mean very different speeds in a narrow pipe versus a wide one.
Result = input rate × (liters-per-minute per source unit ÷ liters-per-minute per target unit). Each unit's L/min factor already bakes in both its volume size and its time interval, so one multiplication does the whole conversion.
Worked examples
Convert 10 US gallons per minute to liters per minute. → 37.8541 L/min
Liters per minute is the base unit, so 10 × 3.78541 = 37.8541 L/min.
Convert 120 liters per minute to cubic meters per hour. → 7.2 m³/h
120 ÷ 16.6667 = 7.2 m³/h, since 1 m³/h equals 16.6667 L/min.
Tips & gotchas
- US and UK (imperial) gallons differ: a UK gallon is about 20 percent larger, so 1 UK GPM (4.54609 L/min) is noticeably more flow than 1 US GPM (3.78541 L/min). Confirm which gallon a spec uses.
- Cubic feet per minute (CFM) is common for air and ventilation. The same volumetric conversion applies, but air flow ratings often assume specific temperature and pressure — check the reference conditions for gases.
- When sizing a pump or pipe, pair the flow rate with the pressure or head and the pipe diameter. Flow rate alone does not tell you whether a system will keep up under load.
- L/s and L/min differ by exactly 60. If a sensor reads in liters per second and a spec is in liters per minute, a missing ×60 is a common and large error.
FAQ
What is the difference between US and UK gallons per minute?
A US gallon is 3.78541 liters and a UK (imperial) gallon is 4.54609 liters — about 20 percent larger. So 1 UK GPM moves more fluid than 1 US GPM, and using the wrong one undersizes or oversizes a system.
Is flow rate the same as flow velocity?
No. Flow rate is the volume passing per unit time; velocity is how fast the fluid moves. For a given flow rate, velocity rises as the pipe narrows. This tool converts volumetric rate, not velocity.
Can I use this for gases like air in CFM?
Yes for the volumetric conversion. Be aware that gas volume depends on temperature and pressure, so air-flow ratings should specify their reference conditions for the numbers to be comparable.
How do I convert liters per second to liters per minute?
Multiply by 60. One liter per second is 60 liters per minute, which is exactly the factor this converter uses.
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