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Reynolds number for a circular pipe

Calculate the dimensionless Reynolds number from density, mean speed, pipe diameter and dynamic viscosity.

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01

Your inputs

The starting values are an example.

Decimals: 12.5 · Thousands: 1,234.56. Follow the field instructions for lists.

02

Your result

Enter your values and select Calculate.

Your calculation will appear here.

Your result will include the relevant values and units.

Understand the calculation

Formula and example

How it is calculated

Re = ρ × v × D ÷ μ

Worked example

1,000 kg/m³, 0.1 m/s, 10 mm and 1 mPa·s give Re = 1,000.

Things to check

  • The input uses dynamic viscosity. The result also shows the corresponding kinematic viscosity.
  • The flow classification is a guide for this geometry. Disturbances and inlet conditions also matter.

Sources and references