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Weir Flow Calculator

Calculate volumetric flow rate over rectangular, triangular, or trapezoidal weirs from the head of water above the weir crest. Used in irrigation canals, wastewater treatment, and stream gauging.

Weir Width/Length (m)

Head Over Weir (m)

Weir Type

Discharge Coefficient

End Contractions

Fill in the required fields to see your result.

Fluid Mechanics

Pipe Flow Calculator

Determine pressure drop in circular pipes using the Darcy-Weisbach equation. Use this when designing water supply lines, HVAC ducts, or industrial piping systems to ensure adequate flow.

Pipe Diameter (m)

Pipe Length (m)

Pipe Material

Flow Velocity (m/s)

Kinematic Viscosity (m²/s)

Fill in the required fields to see your result.

Key differences

	Weir Flow Calculator	Pipe Flow Calculator
Category	Fluid Mechanics	Fluid Mechanics
Inputs required	5	5
Result	Flow Rate (m³/s)	Pressure Drop (Pa)
What it does	Calculate volumetric flow rate over rectangular, triangular, or trapezoidal weirs from the head of water above the weir crest. Used in irrigation canals, wastewater treatment, and stream gauging.	Determine pressure drop in circular pipes using the Darcy-Weisbach equation. Use this when designing water supply lines, HVAC ducts, or industrial piping systems to ensure adequate flow.