Dynamic Viscosity Calculator

Calculate dynamic viscosity from shear stress and shear rate.

About Dynamic Viscosity Calculator

For a Newtonian fluid the ratio of shear stress to shear rate is constant and equals the dynamic viscosity. Non-Newtonian fluids give different ratios at different shear rates, so a single figure is meaningless for them. Many industrial fluids are non-Newtonian, so viscosity must be quoted with the shear rate at which it was measured.

Formula

Dynamic Viscosity

μ = τ ÷ (du/dy), shear stress divided by shear rate

τ: Shear stress
du/dy: Velocity gradient, the shear rate

Worked example

With the default values below, Dynamic Viscosity Calculator returns Dynamic Viscosity of 0.00100000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Shear stressminimum 0 Pa: 2 Pa
Shear rateminimum 0 1/s: 2,000 1/s
Fluid densityminimum 0.01 kg/m3: 1,000 kg/m3

Results

Dynamic Viscosity: 0.00100000 Pa s
Dynamic Viscosity: 1.0000 cP
Kinematic Viscosity: 0.000001000 m2/s
Kinematic Viscosity: 1.0000 cSt
Comparison: Similar to water

Step by step

1Values used
2Dynamic Viscosity
3Dynamic Viscosity= 0.00100000 Pa s
4Dynamic Viscosity= 1.0000 cP
5Kinematic Viscosity= 0.000001000 m2/s
6Kinematic Viscosity= 1.0000 cSt
7Comparison= Similar to water

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 9 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Dynamic Viscosity calculated?

μ = τ ÷ (du/dy), shear stress divided by shear rate For a Newtonian fluid the ratio of shear stress to shear rate is constant and equals the dynamic viscosity. Non-Newtonian fluids give different ratios at different shear rates, so a single figure is meaningless for them.

Why does Dynamic Viscosity matter?

Many industrial fluids are non-Newtonian, so viscosity must be quoted with the shear rate at which it was measured.

What values do I need to enter?

This calculator takes 3 inputs: Shear stress, Shear rate, Fluid density. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.