Reynolds Number Calculator
Estimate whether internal flow is likely laminar, transitional or turbulent from density, velocity, characteristic length and dynamic viscosity.
Reynolds number99,601
Pipe-flow regime guideTurbulent
How this tool works
Re = ρVD/μ, where ρ is density, V velocity, D characteristic length and μ dynamic viscosity.
Example
Water near room temperature moving at 2 m/s through a 50 mm diameter gives Re near 100,000, well into the turbulent pipe-flow range.
Common questions
Are the 2300 and 4000 thresholds universal?
No. They are common guides for fully developed internal pipe flow. Other geometries and disturbances use different transition behavior.
Can I use kinematic viscosity instead?
Yes via Re = VD/ν, but this interface asks for density and dynamic viscosity separately.