Coefficient of Discharge Calculator

Calculate Cᵈ = Qactual / Qtheoretical.

How to Use This Calculator

  1. Measure actual flow rate through the device.
  2. Compute theoretical flow from ideal equations.
  3. Click Calculate to obtain Cᵈ = Qa/Qt.

Formula

Cd = Qa / Qt

Cᵈ accounts for contraction and friction effects, relating ideal to actual discharge.

Frequently Asked Questions

Typical values?

For orifices 0.6–0.65; for Venturi 0.95–0.99, but verify per device.

Units?

Qa and Qt must use the same units; Cᵈ is dimensionless.