Water Viscosity
Get water dynamic viscosity, kinematic viscosity, and density at any temperature 0°C to 100°C. Free online water viscosity calculator with reference charts.
About This Calculator
The Water Viscosity Calculator determines the dynamic viscosity, kinematic viscosity, and density of water at any temperature between 0°C and 100°C. Students, engineers, scientists, and professionals in fluid mechanics, chemical engineering, and environmental science use this tool for accurate water property values.
Water viscosity changes significantly with temperature. At 0°C, water has a dynamic viscosity of 1.788 mPa·s, while at 100°C it drops to 0.2825 mPa·s. This calculator uses standard reference data from NIST and international tables with linear interpolation between data points to provide accurate results at any temperature input. The kinematic viscosity is calculated as the ratio of dynamic viscosity to density: ν = η / ρ.
This calculator is useful for pipe flow analysis (Reynolds number calculation), heat exchanger design, pump selection, HVAC system sizing, chemical process engineering, hydraulic system design, and academic research in fluid dynamics.
Regional Notes
India: This global physics calculator uses SI units (mPa·s, mm²/s, g/cm³) which are standard in Indian engineering and educational institutions following the SI metric system.
United States: While US industries sometimes use centipoise (cP) and centistokes (cSt) — where 1 cP = 1 mPa·s and 1 cSt = 1 mm²/s — this calculator displays values in SI units. For US customary units, multiply mPa·s by 0.000145 to get lb·s/ft².
United Kingdom: UK institutions follow the same SI convention. The results are compatible with British Standards for fluid mechanics and hydraulic engineering applications.
Frequently Asked Questions
What is the viscosity of water at room temperature?
At 20°C (68°F), the dynamic viscosity of water is approximately 1.0016 mPa·s, and the kinematic viscosity is approximately 1.0034 mm²/s. The density of water at this temperature is 0.9982 g/cm³.
How does temperature affect water viscosity?
Water viscosity decreases as temperature increases. At 0°C, water has a dynamic viscosity of 1.788 mPa·s, which drops to 0.2825 mPa·s at 100°C. This happens because higher temperatures increase molecular motion, weakening intermolecular forces and allowing the liquid to flow more freely.
What is the difference between dynamic and kinematic viscosity?
Dynamic viscosity (mPa·s) measures a fluid's internal resistance to flow under an applied force or shear stress. Kinematic viscosity (mm²/s) is the ratio of dynamic viscosity to density, representing how quickly the fluid moves under gravity. The relationship is: kinematic viscosity = dynamic viscosity / density.
Why is water viscosity important?
Water viscosity affects flow in pipes, heat transfer in cooling systems, mixing efficiency in chemical processes, hydraulic engineering, blood flow modeling, and environmental studies of rivers and oceans. Engineers and scientists need accurate viscosity values for designing water-based systems across industries.
How is water viscosity measured?
Water viscosity is commonly measured using a viscometer. The Ostwald viscometer measures kinematic viscosity by timing how long water takes to flow between two marks on a U-shaped glass tube at a controlled temperature. Dynamic viscosity can be measured using rotational viscometers or calculated from density and kinematic viscosity.
Does pressure affect water viscosity?
For most practical applications at atmospheric pressure, pressure has a negligible effect on water viscosity. Temperature is the dominant factor. At very high pressures (thousands of atmospheres), water viscosity does increase, but this is only relevant in specialized applications like deep-sea research or high-pressure industrial processes.
Does adding salt or sugar change water viscosity?
Yes, adding solutes like salt or sugar increases water viscosity. The dissolved particles disrupt the water structure and increase internal friction, making the solution thicker. For example, seawater is slightly more viscous than freshwater, and sugar solutions can be significantly more viscous.
What are the units for water viscosity?
Dynamic viscosity is expressed in millipascal-seconds (mPa·s), which is equivalent to centipoise (cP). Kinematic viscosity is expressed in square millimeters per second (mm²/s), which is equivalent to centistokes (cSt). Density is expressed in grams per cubic centimeter (g/cm³).