Conversion Formula
$$Q_{\text{CFS}} = \frac{Q_{\text{GPM}}}{448.831}$$
Divide the flow in GPM by 448.831 to get cubic feet per second.
GPM to CFS Conversion Table
| US Gallon per Minute (GPM) | Cubic Foot per Second (CFS) |
|---|---|
| 0.1 | 0.000222801 |
| 0.5 | 0.001114 |
| 1 | 0.00222801 |
| 2 | 0.00445602 |
| 5 | 0.01114 |
| 10 | 0.0222801 |
| 25 | 0.0557002 |
| 50 | 0.1114 |
| 100 | 0.222801 |
| 250 | 0.557002 |
| 500 | 1.114 |
| 1,000 | 2.22801 |
GPM to CFS in Engineering
Flow rate conversions are critical for water resources, wastewater treatment, HVAC, and piping design. Civil engineers commonly work with GPM, CFS, and MGD, while mechanical engineers often need CFM for air handling systems.
US Gallon per Minute: Most common US unit for piping, pump, and plumbing flow rates. Essential for fire protection design.
Cubic Foot per Second: Primary US unit for open channel flow, river discharge, and stormwater design. Used by USGS and FEMA.