Dynamic viscosity, also known as absolute viscosity, measures a fluid's internal resistance to flow when subjected to an external force. In engineering, two units are frequently encountered: the Pascal-second (Pa·s) and the Centipoise (cP).
The Pascal-second (Pa·s) is the SI derived unit of dynamic viscosity. It is defined as the viscosity of a fluid in which a stress of one Pascal produces a velocity gradient of one reciprocal second. It is commonly used in scientific research and high-precision fluid mechanics.
The Centipoise (cP) is a CGS (centimeter-gram-second) unit, where 1 cP is equal to 0.001 Pa·s. Despite the prevalence of SI units, the centipoise remains the industry standard in chemical processing, petroleum engineering, and the food industry, largely because the viscosity of water at 20°C is approximately 1 cP.
Pa·s: Used in SI-compliant technical documentation and academic physics.
cP: Preferred in industrial specifications, pump sizing, and material data sheets.
The relationship between these units is defined by the conversion factor: \(1 \text{ Pa·s} = 1000 \text{ cP}\).
Pascal-second to Centipoise Conversion Reference Table
Pascal-second (Pa·s)
Centipoise (cP)
0.1
100
0.5
500
1.0
1000
2.0
2000
5.0
5000
10.0
10000
20.0
20000
50.0
50000
100.0
100000
500.0
500000
1000.0
1000000
Conversion Example: 10 Pa·s to cP
To convert dynamic viscosity from Pascal-seconds to Centipoise, multiply the value by 1000. Follow these steps:
The centipoise is widely used because it provides a convenient scale for common fluids. Since water at room temperature is approximately 1 cP, it serves as a practical reference point for engineers and technicians in the field.
Yes, they are numerically identical. Since 1 Pa·s = 1000 mPa·s and 1 Pa·s = 1000 cP, it follows that 1 mPa·s = 1 cP. Both units are used interchangeably in industrial applications.
"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison." "Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house." — Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)