How to use the dynamic viscosity converter
- Type the viscosity in Value. The default is 1.
- Choose its unit in From, such as centipoise (cP).
- Choose the unit you need in To, such as Pa·s. The answer appears at once.
- Read the table of all eight units below the answer, or press swap to reverse the direction.
What it does and when to use it
Dynamic viscosity, also called absolute viscosity, tells you how thick a fluid is when it is pushed or stirred. Paint, adhesive, food and lab data sheets usually give it in centipoise or mPa·s. Engineering formulas for pipe flow and lubrication use Pa·s, and older US references use lbf·s/ft² or reyn.
Use this converter when a supplier’s cP figure must go into a formula in Pa·s, or when a US textbook value needs to match your SI calculation. If you have the fluid’s density, the density converter gets it into kg/m³ so you can work out kinematic viscosity. If you are not sure which kind of viscosity you have, the combined viscosity converter lists both families and tells you when they cannot be mixed.
How it works
Every unit is stored in pascal-seconds.
| Unit | Pa·s |
|---|---|
| mPa·s, centipoise | 0.001 |
| poise | 0.1 |
| micropoise | 0.0000001 |
| lb/(ft·s) | 1.48816394357 |
| lbf·s/ft² | 47.8802589803 |
| reyn (lbf·s/in²) | 6,894.75729317 |
The poise is the CGS unit, exactly 0.1 Pa·s, and NIST lists it that way. The US units are built from the exact pound (0.45359237 kg), foot (0.3048 m), inch (0.0254 m) and standard gravity (9.80665 m/s²). The tool multiplies by the From factor, divides by the To factor, and shows up to 12 significant figures.
Worked examples
A thick liquid on a data sheet. 250 cP = 0.25 Pa·s, which is 2.5 poise.
A bearing-design unit. 1 reyn = 6,894,757.29317 centipoise (cP). That is why oil viscosities in reyn are tiny numbers.
Water in US units. Water near 25 °C is roughly 0.89 mPa·s. That is 0.000018588036 lbf·s/ft², or 0.000598052388 lb/(ft·s).
Limits and tips
- Always note the temperature with a viscosity value. The converter cannot correct for it.
- Non-Newtonian fluids such as ketchup or paint have a viscosity that changes with stirring speed. Compare values measured at the same shear rate.
- Oil grades such as SAE 10W-30 are not viscosity units, so they cannot be entered here.
Frequently asked questions
Is centipoise the same as mPa·s?
What is the difference between dynamic and kinematic viscosity?
Why are there two pound-based units with different values?
What is a reyn?
Does viscosity change with temperature?
Sources
- NIST Guide to the SI, Appendix B.9: Factors for units listed by kind of quantity (viscosity, dynamic) — NIST, accessed 2026-10-08
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