Enter the viscosity of two or more liquids into the Calculator. The calculator will evaluate the Viscosity Blending Index. 

Viscosity Blending Index Formula

VBI = 14.534 * ln[ln(v + .8)] + 10.975

Variables:

  • VBI is the Viscosity Blending Index ()
  • v is the viscosity of two or more liquid

How to Calculate Viscosity Blending Index?

The following steps outline how to calculate the Viscosity Blending Index.


  1. First, determine the viscosity of two or more liquids. 
  2. Next, gather the formula from above = VBI = 14.534 * ln[ln(v + .8)] + 10.975.
  3. Finally, calculate the Viscosity Blending Index.
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

the viscosity of two or more liquids = 2.234

FAQs

What is viscosity and why is it important?

Viscosity is a measure of a fluid’s resistance to flow. It describes how thick or thin a liquid is. Understanding viscosity is crucial in many industries, such as lubricants, pharmaceuticals, and food production, because it affects how substances behave and interact in different environments and applications.

How do temperature and pressure affect viscosity?

Temperature and pressure have a significant impact on a liquid’s viscosity. Generally, as the temperature increases, viscosity decreases, meaning the liquid flows more easily. Conversely, an increase in pressure can increase viscosity, making a liquid thicker and harder to flow.

What is the difference between dynamic and kinematic viscosity?

Dynamic viscosity, also known as absolute viscosity, measures a fluid’s internal resistance to flow under an applied force. Kinematic viscosity takes the fluid’s density into account and is the dynamic viscosity divided by the density. The choice between these measures depends on the specific application and the characteristics of the fluid being measured.

Can the Viscosity Blending Index be used for all types of liquids?

The Viscosity Blending Index is a useful tool for many, but not all, types of liquids. It is most applicable to liquids that mix well together and have similar chemical properties. For liquids that react chemically or don’t mix well, the VBI may not provide accurate or meaningful results.