Flow Rate Converters
Flow rate describes how much fluid passes a point per unit of time. Plumbers, pool owners, irrigation designers and HVAC engineers all work with it, but the unit changes with the region and trade: gallons per minute for pumps and showers in the US, liters per minute elsewhere, cubic feet per minute for airflow and cubic meters per hour for large systems. These converters help you size pumps, compare specifications and check equipment datasheets.
All flow rate converters
Things to know about flow rate conversions
- Flow rate is a volume per unit of time, so the volume unit and the time unit both matter. Check whether a figure is per second, per minute or per hour.
- US gallons per minute and liters per minute differ by a factor of 3.785, so mixing them can undersize a pump by almost four times.
- Airflow in cubic feet per minute (CFM) can be converted to cubic meters per hour by multiplying by 1.699.
Flow Rate conversion chart
Read across: one of the unit in the left column equals the value shown under each unit.
| 1 unit = | m³/s | m³/h | L/min | L/s | gpm | cfm | cfs |
|---|---|---|---|---|---|---|---|
| m³/s | 1 | 3,600 | 60,000 | 1,000 | 15,850 | 2,119 | 35.31 |
| m³/h | 0.0002778 | 1 | 16.67 | 0.2778 | 4.403 | 0.5886 | 0.00981 |
| L/min | 0.00001667 | 0.06 | 1 | 0.01667 | 0.2642 | 0.03531 | 0.0005886 |
| L/s | 0.001 | 3.6 | 60 | 1 | 15.85 | 2.119 | 0.03531 |
| gpm | 0.00006309 | 0.2271 | 3.785 | 0.06309 | 1 | 0.1337 | 0.002228 |
| cfm | 0.0004719 | 1.699 | 28.32 | 0.4719 | 7.481 | 1 | 0.01667 |
| cfs | 0.02832 | 101.9 | 1,699 | 28.32 | 448.8 | 60 | 1 |
Flow Rate units explained
- Cubic meter per second (m³/s)
- The SI unit of volumetric flow. One m³/s is a very large flow, used for rivers and large pipelines.
- Cubic meter per hour (m³/h)
- Cubic meters per hour is the common metric unit for fans, pumps and water supply systems.
- Liter per minute (L/min)
- Liters per minute is used for taps, showers, small pumps and medical gas flow.
- Liter per second (L/s)
- Liters per second is used for water supply and drainage design.
- US gallon per minute (gpm)
- US gallons per minute is the standard unit for pumps, showers and irrigation in the United States.
- Cubic foot per minute (cfm)
- Cubic feet per minute measures airflow of fans, ventilation systems and air compressors.
- Cubic foot per second (cfs)
- Cubic feet per second is used for river flow and large water systems in the US.