What Is a Viscosity Unit Calculator?
Viscosity describes how much a fluid resists flowing. This calculator converts dynamic viscosity between the three units you'll run into most often — centipoise (cP), Pascal-seconds (Pa·s), and poise — and also computes kinematic viscosity in centistokes (cSt), which factors in the fluid's density.
These conversions come up constantly in engineering, chemistry, food science, and automotive work, where different equipment, spec sheets, and countries use different unit conventions for the same physical property.
How to Read Your Results
Centipoise (cP)
The most commonly used practical unit for dynamic viscosity. Water at room temperature is almost exactly 1 cP, which makes it a handy reference point.
Pascal-seconds (Pa·s)
The SI unit for dynamic viscosity. Since 1 Pa·s equals 1,000 cP, most everyday fluids show a very small Pa·s number — motor oil might be around 0.1 Pa·s.
Poise (P)
A CGS unit still common in older technical literature and some industrial specs. 1 poise equals 100 cP.
Kinematic Viscosity (cSt)
Kinematic viscosity divides dynamic viscosity by density, describing how the fluid flows under gravity alone. This is the number printed on motor oil bottles and used in lubricant grading charts.
Real-World Example
Suppose a lab reports a lubricant's viscosity as 0.085 Pa·s, and the fluid has a density of 0.88 g/cm³ (typical for light motor oil).
| Unit | Value |
|---|---|
| Centipoise (cP) | 85 cP |
| Pascal-seconds (Pa·s) | 0.085 Pa·s |
| Poise | 0.85 P |
| Kinematic viscosity (cSt) | ≈96.6 cSt |
Dividing 85 cP by the 0.88 g/cm³ density gives roughly 96.6 cSt — right in the range you'd expect for a light-to-medium engine oil at operating temperature.
Tips for Working With Viscosity
- Always check the temperature a viscosity value was measured at — viscosity changes dramatically with temperature.
- Water is a quick reference point: about 1 cP at 20°C, 1 cSt kinematic (since its density is ~1 g/cm³).
- Kinematic viscosity needs density — never assume dynamic and kinematic values are interchangeable without dividing by density.
- Oil grading standards (SAE, ISO VG) are based on kinematic viscosity ranges in cSt at a specified temperature.
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Last updated: August 2026 · Reviewed by: Simple Calculator Tools Editorial Team