Enter the kinematic viscosity of the oil at 40°C, the kinematic viscosity of the oil at 100°C, and the kinematic viscosity of a reference oil at 100°C into the calculator to determine the Viscosity Index.

Anton Paar Viscosity Index Formula

The following formula is used to calculate the Viscosity Index (VI) using the Anton Paar Viscosity Index Calculator. 

VI = (L - U) / (L - H) * 100

Variables:

  • VI is the Viscosity Index
  • L is the kinematic viscosity of the oil at 40°C (cSt)
  • U is the kinematic viscosity of the oil at 100°C (cSt)
  • H is the kinematic viscosity of a reference oil at 100°C (cSt)

To calculate the Viscosity Index, subtract the kinematic viscosity of the oil at 100°C from the kinematic viscosity of the oil at 40°C. Then, subtract the kinematic viscosity of a reference oil at 100°C from the kinematic viscosity of the oil at 40°C. Divide the first result by the second result, and multiply the quotient by 100.

What is an Anton Paar Viscosity Index?

The Anton Paar Viscosity Index is a measurement used to determine the change in viscosity of a fluid or oil with temperature. It is a crucial parameter in the lubrication industry as it helps in assessing the performance of lubricating oils under varying temperatures. The index is derived from the viscometer readings at 40°C and 100°C. Higher values of the index indicate a smaller decrease in viscosity with increasing temperature, which is desirable for lubricants. Anton Paar is a company that manufactures instruments for measuring this index.

How to Calculate Anton Paar Viscosity Index?

The following steps outline how to calculate the Anton Paar Viscosity Index (VI).

  1. First, determine the kinematic viscosity of the oil at 40°C (L) in cSt.
  2. Next, determine the kinematic viscosity of the oil at 100°C (U) in cSt.
  3. Next, determine the kinematic viscosity of a reference oil at 100°C (H) in cSt.
  4. Next, use the formula VI = (L – U) / (L – H) * 100 to calculate the Viscosity Index.
  5. Finally, insert the values of L, U, and H into the formula and calculate the Viscosity Index.

Example Problem:

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

kinematic viscosity of the oil at 40°C (L) = 50 cSt

kinematic viscosity of the oil at 100°C (U) = 20 cSt

kinematic viscosity of a reference oil at 100°C (H) = 10 cSt