basic

Reynolds Number Flow Regime Calculator

Re = ρvD/μ — laminar, transitional, or turbulent flow.

Calculates the Reynolds number for pipe or external flow from fluid density, velocity, characteristic length, and dynamic viscosity.

Priya Venkatesan By Priya Venkatesan
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Re = ρ × v × D / μ; <2300=laminar, >4000=turbulent

In depth

Calculates the Reynolds number for pipe or external flow from fluid density, velocity, characteristic length, and dynamic viscosity.