Reynolds Number (Re) & Laminar vs Turbulent Flow Calculator

Calculate dimensionless Reynolds Number in circular pipes to determine whether fluid motion is Laminar ($Re < 2300$) or Turbulent ($Re > 4000$).

Inputs used by this tool

Enter values in the interactive controls when the page loads. The result depends on the assumptions and units shown for each field.

Flow Velocity ($v$, m/s)

Input type: number

Pipe Inside Diameter ($D$, mm)

Input type: number

Kinematic Viscosity ($\nu$, $\times 10^{-6}$ m²/s, Water at 20°C = 1.0)

Input type: number

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