Viscosity Unit Converter
Viscosity describes a fluid's resistance to flow. Dynamic viscosity (also called absolute viscosity) measures the internal friction of a fluid independent of density; kinematic viscosity is dynamic viscosity divided by density. This converter handles both: dynamic units include pascal-seconds (Pa.s), poise (P), and centipoise (cP); kinematic units include square meters per second (m2/s), stokes (St), and centistokes (cSt). Note that converting between dynamic and kinematic units requires knowing the fluid density, which is not included in this converter.
Viscosity conversion factors
Dynamic: 1 Pa.s = 10 P = 1,000 cP = 1,000 mPa.s
Kinematic: 1 m2/s = 10,000 St = 1,000,000 cSt = 1,000,000 mm2/s
Dynamic and kinematic units belong to separate quantity dimensions. Converting between them requires density: kinematic = dynamic / density (kg/m3).
Viscosity unit applications
- Pa.s / mPa.s / cP: Chemical engineering, paint and coating formulations, pharmaceutical rheology. Water at 20 C is 1.002 mPa.s = 1.002 cP.
- Poise (P): Legacy CGS unit in older scientific literature.
- cSt / mm2/s: Lubricant classification (SAE grades), hydraulic fluids, ISO VG grades.
- m2/s / St: Fluid mechanics calculations and scientific research.
Viscosity converter: frequently asked questions
What is the difference between dynamic and kinematic viscosity?
Dynamic viscosity (Pa.s or cP) measures a fluid's resistance to shear stress at any density. Kinematic viscosity (m2/s or cSt) is dynamic viscosity divided by fluid density. For water at 20 C: dynamic = 1.002 cP, kinematic = 1.004 cSt.
What unit is centipoise (cP) and what fluids use it?
Centipoise is 0.001 Pa.s. It is the most common viscosity unit in laboratory and industrial chemistry. Water at 20 C is approximately 1 cP, motor oils range from 50 to 200 cP at 40 C, and honey is around 2,000 to 10,000 cP.
What is a Poise?
The poise (P) is the CGS unit of dynamic viscosity. One poise equals 0.1 Pa.s. It is named after Jean Poiseuille. One centipoise (cP) = 0.01 P = 0.001 Pa.s. The centipoise is more widely used than the poise itself.
What is a centistoke (cSt)?
The centistoke (cSt) is the most common unit of kinematic viscosity. One centistoke = 1 mm2/s = 1e-6 m2/s. Motor oil viscosity grades (SAE 5W-30, 10W-40) correspond to kinematic viscosity ranges at 100 C in cSt.
How does the Stoke relate to kinematic viscosity?
The Stoke (St) is the CGS unit of kinematic viscosity equal to 1 cm2/s = 1e-4 m2/s. One centistoke (cSt) = 0.01 St = 1 mm2/s. The centistoke is used in ASTM standards and SAE viscosity classification.
Official sources
- NIST Special Publication 811: Guide for the Use of the International System of Units (SI).
- BIPM SI Brochure: The International System of Units.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.