# Poise–Stokes Converter (Dynamic to Kinematic Viscosity)

URL: https://speedycalculator.com/calculators/physics/poise-stokes-converter/
Last updated: 2026-10-30

> The poise–stokes converter converts between dynamic viscosity (poise, Pa·s) and kinematic viscosity (stokes, m²/s) using the fluid density.

## Inputs

- Convert from
- Dynamic viscosity η (cP (mPa·s), P, Pa·s)
- Kinematic viscosity ν (cSt (mm²/s), St, m²/s)
- Density ρ (kg/m³, g/cm³, g/mL, lb/ft³, lb/in³)

## Results

- Kinematic viscosity ν
- Dynamic viscosity η

## Formula

```
ν = η / ρ  (1 St = 10⁻⁴ m²/s, 1 P = 0.1 Pa·s)
```

## Explanation

Dynamic viscosity measures a fluid's internal friction; kinematic viscosity divides it by density and governs how fast momentum spreads. Water at 20 °C is about 1 cP and 1 cSt.

### How to use the Poise–Stokes Converter

- **Convert from**
- **Dynamic viscosity η**
- **Kinematic viscosity ν**
- **Density ρ**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

Choose the direction, enter the viscosity and the density.

### Inputs explained

FieldWhat to enterConvert fromChoose one: Dynamic viscosity η, Kinematic viscosity νDynamic viscosity ηUnits: cP (mPa·s), P, Pa·sKinematic viscosity νUnits: cSt (mm²/s), St, m²/sDensity ρUnits: kg/m³, g/cm³, g/mL, lb/ft³, lb/in³

### Example values

How the main result changes when **Dynamic viscosity η** changes and everything else stays at the example values above:

Dynamic viscosity η (cP (mPa·s))Kinematic viscosity ν (cSt (mm²/s))0.5010.50190.75150.752911.00381.251.25481.51.505722.0076

## Worked example

Inputs — Convert from: Dynamic viscosity η; Dynamic viscosity η: 1.002 cP (mPa·s); Density ρ: 998.2 kg/m³.

Results — **Kinematic viscosity ν = 1.003807 cSt (mm²/s)**; Dynamic viscosity η = 1.002 cP (mPa·s).

## Key terms

- **Kinematic viscosity**: Dynamic viscosity divided by density.

## FAQ

**What is a poise?**
0.1 Pa·s, named after Poiseuille.

**What is a stokes?**
1 cm²/s, named after George Stokes.

**Is honey's kinematic viscosity high?**
Yes – thousands of cSt.

**Why can air have a higher ν than water?**
Its density is far lower.


## Sources

- [OpenStax – University Physics Volume 1](https://openstax.org/details/books/university-physics-volume-1)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)