Calculate water flow rate in pipes, channels, or open streams using velocity, area, or volumetric methods.
Water flow rate measures the volume of water passing through a point per unit time (e.g., liters per second or gallons per minute). It's essential for designing plumbing systems, irrigation, and hydraulic engineering. The basic formula is Q = A × v, where Q is flow rate, A is cross-sectional area, and v is velocity. For circular pipes, use A = π × (diameter/2)². The volumetric flow rate concept is widely applied in fluid dynamics.
Common units include cubic meters per second (m³/s), liters per minute (L/min), and gallons per minute (GPM). The EPA recommends consistent units for environmental monitoring. Use our calculator to switch between units effortlessly. For example, 1 GPM ≈ 0.063 L/s, and 1 m³/s = 1000 L/s.
Engineers use flow rate calculations to size pipes, optimize pump efficiency, and ensure wastewater treatment compliance. In agriculture, it helps design drip irrigation systems. The USGS also tracks streamflow for flood prediction. Always account for friction losses (Hazen-Williams equation) in long pipelines.
| Scenario | Input | Flow Rate |
|---|---|---|
| Garden hose (1" diameter, 2 m/s) | A = 0.0005 m², v = 2 m/s | 0.001 m³/s (1 L/s) |
| City water main (6" diameter, 3 ft/s) | A = 0.018 m², v = 0.91 m/s | 0.0164 m³/s (16.4 L/s) |