Viscosity - Dynamic Converter
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| Unit | Equivalent Value |
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Dynamic Viscosity (also known as Absolute Viscosity, Internal Fluid Friction, or Dynamic Shear Resistance, symbolized by μ or η) measures a fluid’s internal resistance to deformation and flow under an applied external shear force (τ = μ · (du ÷ dy) ⇒ μ = τ ÷ (du ÷ dy), where τ is fluid shear stress and du ÷ dy is velocity gradient or shear rate). Across automotive engine oil lubrication rating, hydraulic power transmission, polymer melt extrusion, pipeline crude oil pumping, blood circulation hemodynamics, and food rheology (syrups, sauces, and doughs), dynamic viscosity is categorized across four major engineering unit families: International System of Units (SI metric fundamental: Pascal Second / Pa·s, Newton Second per Square Meter / N·s/m2, Millinewton Second per Sq. Meter / mN·s/m2), CGS Rheology standards (Poise / P, Centipoise / cP, Millipoise / mP, Dyne Second per Sq. Centimeter / dyn·s/cm2), Imperial US/UK Lubrication metrics (Pound-Force Second per Sq. Inch / lbf·s/in2 or Reyn, Pound-Force Second per Sq. Foot / lbf·s/ft2, Slug per Foot Second / slug/(ft·s), Pound per Foot Hour / lb/(ft·h)), and Metric Engineering force units (Kilogram-Force Second per Square Meter / kgf·s/m2).
Our free online Viscosity – Dynamic Converter provides instant, high-precision conversions across all SI metric, CGS centipoise, Imperial lubrication reyn, and fluid mechanics absolute viscosity units:
- Pascal Second to Centipoise [Standard Viscosity Multiplier]:
1 Pa·s = 1,000.0 cP = 10.0 Poise (P) = 1,000.0 mPa·s = 1.0 N·s/m2. - Centipoise to Pascal Second [Fluid Mechanics Standard]:
1 cP = 0.001 Pa·s = 1.0 mPa·s = 0.01 Poise (P) = 0.001 N·s/m2 = 0.001 kg/(m·s). - Poise to Centipoise & Pa·s [CGS Metric Standard]:
1 Poise (P) = 100.0 cP = 0.10 Pa·s = 1.0 dyn·s/cm2 = 1.0 g/(cm·s). - Reyn (lbf·s/in2) to Centipoise & Pa·s [Bearing Lubrication Standard]: Multiply reyn by
6,894.75729(1 reyn = 6,894.76 Pa·s = 6,894,757.29 cP = 144.0 lbf·s/ft2). - Pound-Force Second per Sq. Foot [lbf·s/ft2 / slug/(ft·s)] to Pa·s: Multiply by
47.880259(1 lbf·s/ft2 = 47.8803 Pa·s = 47,880.26 cP = 1.0 slug/(ft·s)). - Pound per Foot Hour [lb/(ft·h)] to Centipoise & Pa·s: Multiply lb/(ft·h) by
0.0004133789(1 lb/(ft·h) = 0.413379 cP = 0.00041338 Pa·s).
Master Dynamic (Absolute) Viscosity Conversion Table
The table below displays exact mathematical conversion relationships, SI Pa·s multipliers, and centipoise (cP) equivalents relative to 1 Pascal Second (1 Pa·s = 1,000 cP = 10 Poise):
| Dynamic Viscosity Unit Name | Symbol | Exact Value in Pa·s | Centipoise (cP) & Poise Equivalent | Domain & Technical Application Standard |
|---|---|---|---|---|
| 1 Pascal Second | Pa·s, N·s/m2 |
1.0 Pa·s (Base SI Unit) |
1,000.0 cP (10.0 Poise / 1,000.0 mPa·s / 1.0 kg/(m·s)) |
SI Fundamental Dynamic Viscosity & Fluid Mechanics Standard |
| 1 Centipoise | cP, mPa·s |
0.001 Pa·s |
1.0 cP (0.01 Poise / 1.0 mPa·s / 0.001 N·s/m2) |
Global Rheology, Chemical & Liquid Viscosity Benchmark |
| 1 Poise | P, dyn·s/cm2 |
0.10 Pa·s |
100.0 cP (0.10 N·s/m2 / 1.0 g/(cm·s)) |
CGS Fundamental Viscosity Unit (Named for Poiseuille) |
| 1 Reyn (lb-force sec / sq. inch) | reyn, lbf·s/in2 |
6,894.75729 Pa·s |
6,894,757 cP (68,947.57 P / 144.0 lbf·s/ft2) |
US Imperial Journal Bearing Hydrodynamic Lubrication |
| 1 Pound-Force Second per Sq. Foot | lbf·s/ft2, slug/(ft·s) |
47.880259 Pa·s |
47,880.26 cP (478.803 P / 1.0 slug/(ft·s)) | Imperial US Engineering Fluid Shear Stress Metric |
| 1 Pound per Foot Second | lb/(ft·s), pdl·s/ft2 |
1.488164 Pa·s |
1,488.16 cP (14.8816 P / 3,600 lb/(ft·h)) | British Imperial Chemical Piping & Heat Transfer |
| 1 Kilogram-Force Second per Sq. Meter | kgf·s/m2 |
9.80665 Pa·s |
9,806.65 cP (98.0665 P / 9.80665 N·s/m2) | European Heavy Hydraulic Press & Viscous Damping |
Step-by-Step Motor Oil & Hydraulic Fluid Viscosity Calculation Example
To convert SAE 30 motor oil with a dynamic viscosity of 200 Centipoise at 20°C (200 cP) into SI Pascal Seconds (Pa·s), CGS Poise (P), and Imperial Reyn (lbf·s/in2):
Step 1 (SI Pa·s Conversion): μ = 200 cP × 0.001 = 0.200 Pa·s (0.20 N·s/m2 or mPa·s = 200)
Step 2 (CGS Poise Conversion): μ = 200 cP ÷ 100 = 2.0 Poise (2.0 P)
Step 3 (Imperial Reyn Conversion): μ = 0.200 Pa·s ÷ 6,894.75729 = 0.000029007 reyn (2.901 × 10-5 reyn)
Thus, SAE 30 motor oil has a dynamic viscosity of 0.20 Pa·s, 2.0 Poise, or 0.000029 reyn.
Real-World Dynamic Viscosity Benchmarks (at 20°C / 68°F)
Below is a comparative reference chart showing dynamic viscosity values (μ) across gases, liquids, lubricants, food products, and heavy polymers:
| Fluid Medium / Substance | Dynamic Viscosity in Centipoise (cP / mPa·s) | SI & CGS Equivalent (Pa·s / Poise P) | Fluid Dynamics & Rheology Engineering Context |
|---|---|---|---|
| Ambient Air (20°C, 1 atm) | 0.01825 cP (18.25 μPa·s) | 0.00001825 Pa·s (0.0001825 P) | Low gas dynamic viscosity driving atmospheric drag |
| Pure Liquid Water (20°C / 68°F) | 1.0016 cP (1.0016 mPa·s) | 0.0010016 Pa·s (0.010016 P) | Universal reference baseline for fluid viscosity |
| Whole Human Blood (37°C Body Temp) | 3.0 – 4.0 cP (3.0 – 4.0 mPa·s) | 0.0030 – 0.0040 Pa·s (0.03 – 0.04 P) | Non-Newtonian physiological blood plasma circulation |
| SAE 30 Automotive Motor Oil (20°C) | 200.0 cP (200.0 mPa·s) | 0.200 Pa·s (2.0 Poise P) | Engine crankcase hydrodynamic film lubrication viscosity |
| Castor Oil / Heavy Liquid Glycerin (20°C) | 985.0 cP (985.0 mPa·s) | 0.985 Pa·s (9.85 Poise P) | Heavy industrial viscous lubricant benchmark |
| Commercial Natural Honey / Molasses (20°C) | 2,000.0 – 10,000.0 cP | 2.0 – 10.0 Pa·s (20 – 100 Poise P) | High-viscosity Newtonian sugar syrup liquid flow |
| Peanut Butter / Commercial Toothpaste (20°C) | 250,000.0 cP (250,000 mPa·s) | 250.0 Pa·s (2,500 Poise P) | Non-Newtonian pseudoplastic paste yield stress flow |
History & Physics: 1687 Sir Isaac Newton Law of Viscosity vs 1840 Jean Poiseuille Flow Law
1687 Sir Isaac Newton & Newton’s Law of Viscosity (τ = μ · (du ÷ dy))
In 1687, Sir Isaac Newton published Philosophiae Naturalis Principia Mathematica, formulating the fundamental law of fluid friction: shear stress (τ) between adjacent fluid layers is directly proportional to velocity gradient (du ÷ dy). Newton defined the constant of proportionality as Dynamic Viscosity (μ) in Pa·s, establishing the scientific definition of Newtonian fluids.
1840 Jean Léonard Marie Poiseuille & The Poise Unit (1 P = 0.1 Pa·s)
In 1840, French physician and physicist Jean Léonard Marie Poiseuille published groundbreaking experimental studies on blood flow through narrow glass capillaries, deriving Hagen-Poiseuille Law (Q = (π · r4 · ΔP) ÷ (8 · μ · L)). To honor his discovery, the CGS unit of dynamic viscosity was named the Poise (P), where 1 Poise = 0.1 Pa·s = 100 Centipoise (cP).
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Frequently Asked Questions (FAQ)
How do you convert centipoise (cP) to Pascal Seconds (Pa·s)?
To convert Dynamic Viscosity from centipoise (cP) to SI Pascal Seconds (Pa·s), divide by 1,000 (or multiply by 0.001). For example, 500 cP ÷ 1,000 = 0.50 Pa·s (0.50 N·s/m2).
Is 1 centipoise (cP) equal to 1 millipascal second (mPa·s)?
Yes, 1 centipoise (cP) is 100% mathematically equal to 1 millipascal second (mPa·s). Both units represent exactly 0.001 Pascal Seconds (0.001 Pa·s).
What is the dynamic viscosity of pure water at 20°C?
At 20°C (68°F), the dynamic viscosity of pure liquid water is 1.0016 cP (1.0016 mPa·s or 0.0010016 Pa·s). For general engineering calculations, water viscosity is rounded to 1.0 cP.
What is the difference between Dynamic Viscosity (μ) and Kinematic Viscosity (ν)?
Dynamic Viscosity (μ in cP or Pa·s) measures internal fluid shear resistance under force. Kinematic Viscosity (ν in cSt or m2/s) measures fluid flow resistance under gravity, calculated by dividing dynamic viscosity by fluid density: ν = μ ÷ ρ.