Flow Rate Converter
Convert between cubic meters/second, liters/second, liters/minute, GPM, and cubic feet/second.
How flow rate conversion works
Flow rate measures volume moving past a point over time, so every unit here combines a volume unit (cubic meters, liters, gallons, cubic feet) with a time unit (seconds, minutes). Everything converts through cubic meters per second, the SI unit.
Multiply your value by the cubic meters per second in its unit, then divide by the figure for the target unit. Going between seconds and minutes is a factor of 60, and between liters and cubic meters a factor of 1,000.
Worked example
A pump is rated at 25 GPM. In liters per minute that is 25 × 3.7854 ≈ 94.64 L/min. Dividing by 60 gives about 1.58 L/s.
Common conversions
| Conversion | Result |
|---|---|
| 1 GPM in liters per minute | 3.785412 L/min |
| 1 GPM in liters per second | 0.06309 L/s |
| 1 L/s in liters per minute | 60 L/min |
| 1 L/s in GPM | 15.850323 GPM |
| 100 L/min in GPM | 26.417205 GPM |
| 1 ft³/s in GPM | 448.831169 GPM |
| 1 ft³/s in liters per second | 28.316847 L/s |
| 1 m³/s in liters per minute | 60,000 L/min |
Choosing and comparing ratings
Ratings are only comparable once they use the same unit and the same gallon. The GPM here is the US gallon; a UK (imperial) gallon is about 20% larger, so a UK-rated pump delivers more per gallon than the same number in US GPM. This converter does not include cubic feet per minute, the unit often used for airflow. Flow rate also says nothing about pressure, so a fixture or pump needs checking on both.
Frequently asked questions
What is GPM commonly used for?
GPM (US gallons per minute) is the standard unit for rating pumps, faucets, showerheads, and irrigation systems in the US — plumbing fixtures are frequently labeled with a maximum GPM flow rating.
Why does flow rate matter beyond just volume?
The same total volume delivered quickly vs. slowly has very different practical implications — pipe sizing, pump power requirements, and how fast a tank fills or drains all depend on the rate, not just the total amount.