Popular conversions
1 pairsPascal-Second ↔ Centipoise
Pa·s ↔ cP
Unit guides
2 unitsDynamic Viscosity calculators
1 toolsDetailed guide to Dynamic Viscosity
Dynamic viscosity describes a fluid's internal resistance to flow — its 'thickness.' It is a key input for the Reynolds number and fluid-flow calculations.
The pascal-second is the SI unit of dynamic viscosity, while centipoise is the practical unit most often used in industry.
- Physical quantity
- Dynamic viscosity
- SI unit
- Pascal-second
- SI symbol
- Pa·s
- Water viscosity
- ≈ 0.001 Pa·s (1 cP) at 20 °C
- Typical use
- Reynolds number, lubricants and process fluids
What is dynamic viscosity?
Dynamic viscosity measures a fluid's resistance to shear, i.e. how hard it is to slide one layer of fluid past another.
High-viscosity fluids like honey flow slowly; low-viscosity fluids like water flow easily.
Pascal-second and centipoise
One pascal-second equals exactly 1,000 centipoise. Centipoise is preferred in industry because common liquids produce more readable numbers in that scale.
Water at 20 °C has a viscosity of about 1 centipoise (0.001 Pa·s), which is often used as a practical reference point.
Viscosity in the Reynolds number
The Reynolds number (Re = ρvD/μ) uses dynamic viscosity directly and determines whether a flow is laminar or turbulent — critical for pipe design and aerodynamics.
Dynamic viscosity should not be confused with kinematic viscosity (ν = μ/ρ), which factors in the fluid's density as well.
Dynamic viscosity units
| Unit | Symbol | Information |
|---|---|---|
| Pascal-Second | Pa·s | View unit guide |
| Centipoise | cP | View unit guide |
Sources
The definitions and conversion relationships on this page are aligned with standard metrology and SI reference material.