A flow rate converter moves a volumetric flow between the units pumps, plumbers and HVAC engineers use: m³/s and L/s in SI, m³/h and L/min in everyday metric, and GPM (US gallons per minute) and CFM (cubic feet per minute) in the US. It converts your value into a base unit — cubic metres per second — and back out. Flow rate is simply volume per unit time, so the same machinery that converts volumes drives this, scaled by the time unit.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: SI and US volume/time factors, recomputed in code.
How the conversion works
Each unit equals a fixed flow in cubic metres per second. Multiply your value by the "from" unit's m³/s-per-unit to reach the base, then divide by the "to" unit's. The metric chain is clean — 1 L/s is 3.6 m³/h because there are 3600 seconds in an hour and 1000 litres in a cubic metre. GPM and CFM bring in the US gallon (3.785412 L) and cubic foot (28.3168 L) respectively.
Worked example — 1 L/s in other units
Scenario: convert a flow of 1 litre per second to other units.
One litre per second is 3.6 m³/h, 60 L/min, 15.8503 US GPM, or 2.11888 CFM. The reverse cases follow the same rule: 1 US GPM is 0.06309 L/s (3.785412 L/min), 1 m³/h is 0.277778 L/s (4.40287 GPM), and 1 CFM is 0.47195 L/s. The converter shows every supported unit at once — exactly what pump and ventilation specs need.
Frequently Asked Questions
× 3.6. 1 L/s = 3.6 m³/h = 60 L/min.
× 3.785412 (US gallon). 1 GPM = 3.785412 L/min = 0.06309 L/s.
Cubic feet/min (airflow). 1 CFM = 0.47195 L/s = 1.699 m³/h.
US (3.785 L). UK imperial is ~20% larger (4.546 L).
Volume ÷ time. 1 L/s delivers 3600 L (3.6 m³) per hour.