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Prandtl Number Calculator — Viscosity, Heat Capacity & Thermal Conductivity

Calculate Prandtl number from dynamic viscosity, specific heat and thermal conductivity.

Last updated: September 17, 2026

Results

Enter positive μ, cp and thermal conductivity

Formula, example and assumptions

Pr=μcp/k=ν/α.

For air near room conditions Pr is roughly 0.7, while many liquids have larger values.

  • Fluid properties should be evaluated at an appropriate representative temperature.
  • Use mutually consistent SI units for μ, cp and k.

FAQs

What does Prandtl number compare?

It compares momentum diffusivity with thermal diffusivity.

Is Prandtl number dimensionless?

Yes. With consistent units the dimensions cancel.