Skip to content
Calculation Machine

Reynolds Number Calculator

Laminar or turbulent flow test.

Reviewed by the Calculation Machine team · How we check our maths

Your values

ⓘ Live results

Results
Reynolds number
59,880
Flow regime
Turbulent
Kinematic viscosity
0.000001 m²/s
Velocity for Re = 2300
0.04609 m/s

Quick answer

The Reynolds number compares inertial to viscous forces; below 2300 flow is laminar, above 4000 turbulent.

The formula

Re = ρvD / μ

Worked example

Worked example

Using the values the calculator loads with.

Inputs

  • Fluid density998 kg/m³
  • Velocity1.2 m/s
  • Pipe diameter0.05 m
  • Dynamic viscosity0.001 Pa·s

Result

  • Reynolds number59,880
  • Flow regimeTurbulent
  • Kinematic viscosity0.000001 m²/s
  • Velocity for Re = 23000.04609 m/s

How to use the Reynolds Number Calculator

  1. 1Enter fluid density and viscosity.
  2. 2Enter flow velocity and pipe diameter in SI units.
  3. 3Read the regime classification.

Frequently asked questions

Water at room temperature?

Density 998 kg/m³, viscosity about 0.001 Pa·s.

Why does the regime matter?

Turbulent flow mixes better but causes far higher pressure loss.

About this calculator