What is the formula used?

ν = μ / ρ, where ν is kinematic viscosity (m²/s), μ is dynamic viscosity (Pa·s), and ρ is density (kg/m³). For reverse mode: μ = ν × ρ.

What is the difference between dynamic and kinematic viscosity?

Dynamic (absolute) viscosity μ measures a fluid's internal resistance to shear stress. Kinematic viscosity ν additionally accounts for density, representing how quickly the fluid flows under its own weight.

What units does this calculator support?

Dynamic viscosity: Pa·s and cP (centipoise, where 1 Pa·s = 1000 cP). Density: kg/m³ and g/cm³ (where 1 g/cm³ = 1000 kg/m³). Kinematic viscosity: m²/s and cSt (centistokes, where 1 m²/s = 10⁶ cSt).

What is the kinematic viscosity of water at 20°C?

Water at 20°C has a dynamic viscosity of about 1.002 mPa·s (1.002 cP) and a density of 998.2 kg/m³, giving a kinematic viscosity of approximately 1.004 × 10⁻⁶ m²/s (1.004 cSt).

Why is kinematic viscosity used instead of dynamic viscosity?

Many flow problems (pipe flow, Reynolds number, Stokes settling) depend on the ratio μ/ρ rather than μ alone. Kinematic viscosity bundles this ratio into a single quantity, simplifying equations.

Kinematic Viscosity Calculator

Name: Kinematic Viscosity Calculator
Availability: InStock
Author: Nham Vu

Convert between dynamic viscosity and kinematic viscosity using fluid density. Supports Pa·s, cP, m²/s, and cSt units.

Inputs

Calculation Mode

Dynamic Viscosity (μ)

Fluid Density (ρ)

Enter values on the left to calculate

Summary

Convert between dynamic viscosity and kinematic viscosity using fluid density. Supports Pa·s, cP, m²/s, and cSt units.

How it works

Select the calculation direction: ν from μ and ρ, or μ from ν and ρ.
Choose your preferred units for each input field.
Enter values in the input fields.
The result appears instantly in both m²/s and cSt (or Pa·s and cP).
Use the Reset button to clear all fields and start over.

Use cases

Determine kinematic viscosity of engine oil from its dynamic viscosity and density.
Verify lubricant grade (ISO VG) by checking kinematic viscosity at 40°C.
Back-calculate dynamic viscosity when kinematic viscosity and density are known.
Convert cP and g/cm³ lab measurements to SI units for engineering calculations.
Compute Reynolds number inputs for pipe-flow or airfoil CFD simulations.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu