Welcome to our page about Reynolds number! The Reynolds number is a dimensionless quantity used for the categorisation of fluid flows as either turbulent or laminar. It is calculated as the ratio of inertial forces to viscous forces, with higher Reynolds numbers indicating turbulent flow.
Here we'll provide some more information and a calculation to categorise your flows!


⬇️ Inputs

Velocity (m/s)


Kinematic Viscosity (m^2/s)

⬆️ Outputs

Reynolds Number

💬 We'd love your feedback on this template! It takes 1min


Reynolds number can be defined as the ratio of internal forces to the viscous forces within a fluid experiencing relative internal movement due to different fluid velocities.

For most practical purposes concerning pipes, if the Reynolds number is below 2300 the flow is considered to be laminar. If the Reynolds number is between 2300 and 4000 the flow is considered transitional. A Reynolds number above 4000 suggests turbulent flow.

📖 Laminar vs Turbulent Flow

These critical values do vary depending on various factors related to different situations, so it is important to ensure that the correct critical value is being used.
The Reynolds number of fluid is calculated using the following equation;


🕵️‍♀️ Who was Osborne Reynolds?

Additional Resources

For another similar calculator, check out our Mach Number Calculator!

💬 Got 1min to provide feedback on this template? Click here