Reynolds Number Calculator

The Reynolds Number (Re)is a dimentionless number, helps to predict whether the fluid flow will be laminar or turbulent. To make your calculation easy, we are with Reynolds Number Calculator.

Calculate Reynolds number for fluid flow analysis

Density (ρ)

kg/m³

Velocity (v)

m/s

Characteristic Length (L)

m (pipe diameter, etc.)

Dynamic Viscosity (μ)

Pa·s

How to Use the Reynolds Number Calculator

How to Use the Calculator

Enter the fluid density, velocity, diameter (or characteristic length), and dynamic viscosity.
Click 'Calculate'.

The tool will display the Reynolds number and the flow regime:
Laminar: Re < 2000
Transitional: 2000 < Re < 4000
Turbulent: Re > 4000

What is Reynolds' law?

The Reynolds number (Re) is a dimensionless value that compares inertial forces to viscous forces in a fluid. It's widely used to predict the flow pattern in a pipe or over a surface.

$\text{Reynolds number: } \text{Re} = \frac{\rho V L}{\mu}$

$\text{Where:}$
$\rho = \text{fluid density}$
$V = \text{characteristic velocity}$
$L = \text{characteristic length}$
$\mu = \text{dynamic viscosity}$