Viscosity converter
ν = η / ρ
Convert a dynamic viscosity (pascal-second, millipascal-second, centipoise, poise) or a kinematic viscosity (square meter per second, centistokes, stokes). The two quantities are kept separate: going from one to the other requires the fluid density, which this tool does not do silently.
1 Centipoise (cP) = 1 Millipascal-second (mPa·s)
Raw value: 1
Scientific dossier
What the tool computes, what it assumes, where it stops being valid, and where its data comes from.
Method & formulasν = η / ρ
ν = η / ρ
1 cP = 1 mPa·s (exactly)
1 cSt = 1 mm²/s (exactly)
Kinematic viscosity ν is the ratio of dynamic viscosity η to density ρ. The two numerical coincidences above explain the lasting popularity of the centipoise and centistokes: at room temperature water is very nearly exactly 1 cP and about 1 cSt.
- µPa·s
- · Micropascal-second (µPa·s)
- mPa·s
- · Millipascal-second (mPa·s)
- Pa·s
- · Pascal-second (Pa·s)
- cP
- · Centipoise (cP)
- P
- · Poise (P)
- mm²/s
- · Square millimeter per second (mm²/s)
- cm²/s
- · Square centimeter per second (cm²/s)
- m²/s
- · Square meter per second (m²/s)
- cSt
- · Centistokes (cSt)
- St
- · Stokes (St)
Validity domainGoing from dynamic to kinematic viscosity requires knowing the fluid density: this is not a unit conversion but a one-parameter physical calculation.
Going from dynamic to kinematic viscosity requires knowing the fluid density: this is not a unit conversion but a one-parameter physical calculation. A converter accepting it without asking for ρ would implicitly apply the density of water, and would silently produce a wrong result for any other fluid. Photoresist datasheets, for instance, quote viscosity in cSt: SU-8 2025 is given as 4500 cSt at a density of 1.219 g/mL, far from that of water.