Reynolds Number Calculator

Calculate the Reynolds number to predict flow regime (laminar vs turbulent).

Flow Parameters

Use consistent units (e.g. SI)

Fluid Density (ρ)

Flow Velocity (v)

Characteristic Length (L) (Diameter for pipe)

Dynamic Viscosity (μ)

Reynolds Number

Enter fluid properties

Quick Reference

ρDensity

vVelocity

LCharacteristic Length

μDynamic Viscosity

Overview

The Reynolds number is a dimensionless quantity in fluid mechanics used to help predict flow patterns in different fluid flow situations.

💡

Pro Tips

Re < 2300: Laminar flow (smooth, constant fluid motion).
2300 < Re < 4000: Transitional flow.
Re > 4000: Turbulent flow (chaotic, eddies).
Ensure all units are consistent (e.g., SI units: kg/m³, m/s, m, Pa·s).

Fun Facts

"Osborne Reynolds popularized this concept in 1883."
"It represents the ratio of inertial forces to viscous forces."
"Microfluidic devices typically operate at very low Reynolds numbers."

Formula: Re = (ρvL) / μ

Used with this

Similar tools that might be useful

Absolute Humidity

Ac Wattage

Acceleration