Dynamic viscosity (μ, in centipoise) and kinematic viscosity (ν, in centistokes) are linked by the fluid's density: μ = ν × ρ. This free converter solves for the dynamic viscosity, the kinematic viscosity, or the density, and shows every step.
Dynamic viscosity is kinematic viscosity times density, μ = ν · ρ. This one relation lets you move freely between the two ways of measuring how a fluid resists flow. In SI, μ is in pascal-seconds (Pa·s) and ν in square metres per second (m²/s); in the common industrial units, 1 centipoise (cP) = 1 mPa·s and 1 centistokes (cSt) = 1 mm²/s. The density ρ is the bridge between them, so you always need it — or a value to solve for it.
Using the converter is simple: enter any two of the three quantities and read the third. Choose what you want in the Solve for menu, then type the values you know in whatever units suit you — the tool rescales everything to base SI, computes the answer, and shows the substituted formula step by step. To find a fluid's density first, use the density calculator; to see how viscosity feeds into pressure and flow speed, try the Bernoulli equation calculator.
Water at 20 °C has a kinematic viscosity of about 1.0 cSt and a density of 1000 kg/m³. Its dynamic viscosity is μ = ν · ρ = 1.0×10-6 m²/s × 1000 kg/m³ = 1.0×10-3 Pa·s = 1.0 cP. Because water's density is about 1 g/cm³, its cSt and cP values come out almost equal — a handy sanity check whenever you convert between the two units.
Lubricant grades (engine oils, hydraulic fluids), pumping and pipeline design, coatings and food processing all specify viscosity, but instruments may report kinematic values (a flow cup) or dynamic values (a rotational viscometer). Converting between cSt and cP via density is therefore a daily task in engineering. The same fluid property governs how bodies move through a fluid — see the drag force calculator — and you can look up any unfamiliar term in the physics glossary.
Dynamic viscosity (μ) measures a fluid's internal resistance to shear; kinematic viscosity (ν) is that divided by density, ν = μ/ρ, so μ = ν × ρ.
Multiply the cSt value by the density in g/cm³: cP = cSt × (density in g/cm³). For water (about 1 g/cm³) the numbers are nearly the same.
1 cP = 0.001 Pa·s (1 mPa·s) and 1 cSt = 1e-6 m²/s (1 mm²/s).
Because kinematic viscosity already has the density divided out; to get back to dynamic viscosity you multiply the density in again.
Water is about 1 cP, light engine oil tens of cP, honey a few thousand cP; in cSt, water is about 1 cSt and an SAE 30 oil around 100 cSt at 40 °C.