Viscosity Converter
A specialized tool to convert between various dynamic viscosity units like Pascal-seconds, Poise, and Centipoise.
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About this tool
Convert dynamic viscosity (resistance to flow) between pascal-second (Pa·s), millipascal-second (mPa·s), kilopascal-second (kPa·s), poise (P), centipoise (cP), gram per centimeter-second (g/cm·s) and the imperial units pound-force second per square foot (lbf·s/ft²), pound-force second per square inch (lbf·s/in²) and poundal second per square foot (pdl·s/ft²). The menus show full names with symbols, and the result is labeled with the symbol. Centipoise equals millipascal-second, and water at 20 °C is about 1 cP. Conversions pass through Pa·s. This is dynamic viscosity only, not kinematic viscosity (stokes or cSt), which needs fluid density. Results show up to 8 decimals.
How to use it
- Type the value to convert.
- Choose the From and To units.
- Read the result, which updates as you type.
- Use Swap to reverse the units or Copy to copy the result.
Example
One pascal-second is 1,000 centipoise.
1 Pa·s to cP
1000 cP
Viscosity units in pascal-seconds
Every conversion goes through Pa·s. These are the factors the tool uses.
- 1 Pa·s
- 10 P = 1,000 cP = 1,000 mPa·s
- 1 P (poise)
- 0.1 Pa·s = 100 cP. Same as 1 g/cm·s.
- 1 cP (centipoise)
- 0.001 Pa·s = 1 mPa·s
- 1 kPa·s
- 1,000 Pa·s
- 1 lbf·s/ft²
- about 47.88 Pa·s
- 1 lbf·s/in²
- about 6,894.76 Pa·s
- 1 pdl·s/ft²
- about 1.488 Pa·s
Dynamic vs kinematic viscosity (cP to cSt)
Dynamic viscosity (Pa·s, poise, cP) is a fluid's resistance to flow under a force. Kinematic viscosity (m²/s, stokes, cSt) is dynamic viscosity divided by density, and is what gravity-flow tests such as cup and capillary viscometers measure.
To go between them you need the fluid's density at the same temperature. With density in g/cm³, centistokes equal centipoise divided by density.
cSt = cP / density (g/cm³) cP = cSt x density (g/cm³) Oil at 100 cP with density 0.9 g/cm³: 100 / 0.9 = 111.1 cSt
Temperature matters
Viscosity changes strongly with temperature. Liquids get thinner as they warm up, so a value is only meaningful with the temperature it was measured at. Converting units does not change that temperature.
Common problems
- Kinematic viscosity (cSt) is not supported
- Stokes and centistokes depend on density. This tool converts dynamic viscosity only.
- Poise and g/cm·s give the same number
- They are the same unit, so both equal 0.1 Pa·s.
- cP and mPa·s
- They are numerically equal, so converting between them leaves the number unchanged.
Frequently asked questions
Is cps the same as cP?
Yes. cps is an older abbreviation for centipoise, still common on data sheets. 1 cps = 1 cP = 1 mPa·s.
How many centipoise are in a poise?
100. The prefix centi means one hundredth, so 1 P = 100 cP.
What is the SI unit of viscosity?
The pascal-second (Pa·s) for dynamic viscosity and the square metre per second (m²/s) for kinematic viscosity. This tool covers dynamic viscosity only.