PipeSageWhen to use this calculator
This is the standard thin-plate orifice equation used for flow metering. Cd (discharge coefficient) accounts for the vena contracta and typically runs 0.60–0.65 for a sharp-edged concentric orifice at high Reynolds numbers — use the value from your orifice plate's calibration sheet if you have one, since Cd varies with beta ratio and Reynolds number in precision applications.