About Viscosity Conversion
Viscosity conversions are used in chemical engineering, lubricants, and fluid mechanics.
Dynamic and kinematic viscosity
Viscosity comes in two kinds. Dynamic viscosity measures resistance to shear, in pascal-seconds, poise or centipoise: 1 P is 100 cP, and 1 cP is 0.001 Pa·s, the same as 1 mPa·s. Kinematic viscosity is dynamic viscosity divided by density, in square meters per second, stokes or centistokes: 1 St is 100 cSt, and 1 cSt is 10⁻⁶ m²/s, the same as 1 mm²/s.
This converter changes units within each kind. Converting between the kinds, such as cP to cSt, needs the fluid's density, which the kinematic viscosity calculator takes into account.
Typical viscosities at 20 °C
- Water: about 1.0 cP, or 1.0 cSt
- Ethanol: about 1.2 cP
- Olive oil: about 80 cP
- Glycerol: about 1,410 cP
- Honey: several thousand cP, depending on the honey and its water content
Viscosity and temperature
Viscosity drops quickly as liquids warm, so a figure without a temperature means little. Lubricant data sheets give kinematic viscosity at 40 °C and 100 °C, and ISO viscosity grades are named after the value at 40 °C: ISO VG 46 is 46 cSt, give or take 10%.