Pascal-Seconds to Centipoise Viscosity Converter
Common Conversions
| Pa·s | cP |
|---|---|
| 0.0001 | 0.1 |
| 0.0005 | 0.5 |
| 0.001 | 1 |
| 0.002 | 2 |
| 0.005 | 5 |
| 0.01 | 10 |
| 0.025 | 25 |
| 0.05 | 50 |
| 0.1 | 100 |
| 1 | 1000 |
Why this conversion matters in chemistry
Pharmaceutical formulation is the usual culprit. A 0.025 Pa·s reading off a rheometer for a shear-thinning carboxymethylcellulose gel becomes 25 cP — the form USP <911> expects to see for a topical-cream release test. The factor of 1000 is straightforward: 1 cP = 1 mPa·s, which is the centipoise written as a milli-prefixed SI unit. Underneath that, 1 cP is also 0.01 P (poise, CGS), but nobody outside historical references writes in plain poise anymore.
Formula
cP = Pa·s × 1000
Worked Examples
0.001 Pa·s = 1 cP
Water at 20 °C — the calibration anchor at the low-viscosity end.
1 Pa·s = 1000 cP
About a thick syrup-like viscosity.
0.00089 Pa·s = 0.89 cP
Water at 25 °C — useful as a temperature-corrected reference.
Frequently Asked Questions
How do I convert Pa·s to cP?
Multiply by 1000. So 1 Pa·s = 1000 cP. Equivalently, 1 Pa·s = 1000 mPa·s and 1 cP = 1 mPa·s — exact through the centi prefix.
What's the difference between dynamic and kinematic viscosity?
Dynamic viscosity (Pa·s or cP) measures resistance to flow under applied shear stress. Kinematic viscosity (m²/s or St) is dynamic viscosity divided by density. Both describe fluid flow but from different angles — dynamic is the natural choice for force-related calculations, kinematic for gravity-driven flow.
How does viscosity affect reaction rates?
Higher viscosity slows diffusion via the Stokes-Einstein equation D = kT/(6πηr), reducing the rate of diffusion-controlled bimolecular reactions. Highly viscous solvents like glycerol can knock orders of magnitude off second-order rate constants for fast reactions.