Free Online Viscosity Converter

Free Online Viscosity Conversion Tool

Our comprehensive Viscosity Converter is an essential tool for engineers, chemists, lubricant specialists, and anyone working with fluid dynamics. This powerful converter allows you to instantly convert between dozens of viscosity units including pascal-seconds, centipoise, stokes, centistokes, reyn, and many more. Whether you're designing hydraulic systems, formulating lubricants, analyzing fluid flow, or working in petroleum engineering, this tool provides accurate conversions with real-time results.

How to Use This Viscosity Converter (Step-by-Step):

• Enter Value: Input the numerical viscosity value you want to convert in the "Viscosity Value" field
• Select Source Unit: Choose the unit of your input value from the dropdown menu (e.g., centipoise, Pa·s, cSt)
• View Results: Instantly see the converted values in all major viscosity units in the results panel
• Additional Actions: Use the buttons to copy results, swap units, or reset the converter for new calculations

Real-Life Application Examples:

For Lubricant Engineering: Convert between different viscosity units when specifying lubricant grades. SAE 30 motor oil has a viscosity of approximately 200-300 centipoise at 40°C, which equals 0.2-0.3 Pa·s or about 0.000003-0.000004 reyn.

For Chemical Processing: Convert viscosity measurements when working with different fluid systems. A polymer solution with viscosity of 5,000 cP equals 5 Pa·s, helping engineers design appropriate pumping and mixing equipment.

For Petroleum Industry: Convert between kinematic and dynamic viscosity units for crude oil characterization. Crude oil with kinematic viscosity of 15 cSt and density 0.85 g/cm³ has dynamic viscosity of 12.75 cP.

For Quality Control: Convert viscosity measurements between different standards and testing methods used in various industries and geographical regions.

Common Viscosity Unit Definitions:

• Pascal-second (Pa·s): SI unit of dynamic viscosity - force per unit area required to maintain unit velocity gradient
• Centipoise (cP): Most commonly used unit of dynamic viscosity - 1 cP = 0.001 Pa·s
• Poise (P): CGS unit of dynamic viscosity - named after Jean Léonard Marie Poiseuille
• Stokes (St): CGS unit of kinematic viscosity - dynamic viscosity divided by density
• Centistokes (cSt): Most commonly used unit of kinematic viscosity - 1 cSt = 0.01 St
• Reyn: Imperial unit of dynamic viscosity - named after Osbourne Reynolds, used in lubrication engineering
• lb·ft⁻¹·s: Imperial unit of dynamic viscosity - pound-force second per square foot

Who Should Use This Viscosity Converter?

• Mechanical Engineers: Essential for designing hydraulic systems, bearings, and lubrication systems
• Chemical Engineers: Perfect for process design, fluid dynamics, and material characterization
• Lubricant Specialists: Ideal for formulating and testing oils, greases, and synthetic lubricants
• Petroleum Engineers: Useful for crude oil characterization and pipeline design
• Quality Control Technicians: Valuable for verifying product specifications across different measurement systems
• Students & Educators: Great for engineering, chemistry, and physics courses dealing with fluid mechanics

Frequently Asked Questions

What's the difference between dynamic and kinematic viscosity?
Dynamic viscosity measures a fluid's resistance to flow (internal friction), while kinematic viscosity is dynamic viscosity divided by density. Kinematic viscosity accounts for both the fluid's resistance to flow and its density.

How do I convert between dynamic and kinematic viscosity?
Kinematic viscosity = Dynamic viscosity ÷ Density. You need to know the fluid's density to convert between these two types of viscosity measurements.

Why are centipoise and centistokes so commonly used?
Centipoise and centistokes provide convenient numerical values for most practical applications. Water has viscosity of approximately 1 cP at 20°C, making it easy to compare other fluids relative to water.

How accurate are the conversions?
Our converter uses precise conversion factors based on international standards. For most engineering and scientific purposes, the accuracy is more than sufficient.

Can I convert viscosity at different temperatures?
This converter handles unit conversions only. Viscosity is highly temperature-dependent, so temperature-specific conversions require additional calculations based on the fluid's viscosity-temperature relationship.

Viscosity Conversion Factors Reference:

For quick reference, here are some key conversion factors:

• 1 Pa·s = 1,000 cP = 10 P = 0.0209 lb·ft⁻¹·s
• 1 cP = 0.001 Pa·s = 0.01 P = 0.000000145 Reyn
• 1 P = 100 cP = 0.1 Pa·s = 0.00209 lb·ft⁻¹·s
• 1 St = 100 cSt = 0.0001 m²/s
• 1 cSt = 0.01 St = 0.000001 m²/s
• 1 Reyn = 68,950 P = 6,895,000 cP
• 1 lb·ft⁻¹·s = 47,880 cP = 478.8 P

Typical Viscosity Values by Fluid Type:

• Air (20°C): 0.018 cP
• Water (20°C): 1.0 cP
• Blood (37°C): 3-4 cP
• Olive Oil (20°C): 80-100 cP
• SAE 10W Motor Oil (20°C): 100-200 cP
• SAE 30 Motor Oil (20°C): 200-300 cP
• Honey (20°C): 2,000-10,000 cP
• Ketchup: 50,000-100,000 cP
• Peanut Butter: 150,000-250,000 cP

Viscosity Classification Systems:

• SAE J300: Engine oil viscosity classification (e.g., SAE 5W-30)
• SAE J306: Gear oil viscosity classification
• ISO 3448: Industrial oil viscosity classification
• ASTM D445: Standard test method for kinematic viscosity
• These systems help standardize viscosity measurements across different applications and industries

Temperature Effects on Viscosity:

• Viscosity decreases as temperature increases for most liquids
• Viscosity increases as temperature increases for most gases
• The relationship is often described by the Arrhenius equation or Vogel-Fulcher-Tammann equation
• Viscosity index (VI) measures how much viscosity changes with temperature