The poise (symbol P; IPA: /pwɑːz/) is the unit of dynamic viscosity in the centimetre gram second system of units. It is named after Jean Louis Marie Poiseuille.
- 1 P = 1 g·cm−1·s−1
The analogous unit in the International System of Units is the pascal second (Pa·s):
- 1 Pa·s = 1 kg·m−1·s−1 = 10 P
The poise is often used with the metric prefix centi-. A centipoise is one millipascal-second (mPa·s) in SI units. (1 cP = 10-2P = 10-3 Pa·s) Centipoise is properly abbreviated cP, but the alternate abbreviations cps and cPs are also commonly seen. Water has a viscosity of 0.0089 poise at 25 °C, or 1 centipoise at 20 °C.
