Enter the kinematic viscosity of oil at 40C of 0, the kinematic viscosity of lubricant, and the kinematic viscosity of oil at 40C of 100 into the Viscosity Index Calculator. The calculator will evaluate the Viscosity Index.

## Viscosity Index Formula

The following formula is used to calculate the Viscosity Index.

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

Variables:

• VI is the Viscosity Index ( )
• L is the kinematic viscosity of oil at 40C of 0
• U is the kinematic viscosity of lubricant
• H is the kinematic viscosity of oil at 40C of 100

## How to Calculate Viscosity Index?

The following steps outline how to calculate the Viscosity Index.

1. First, determine the kinematic viscosity of oil at 40C of 0.
2. Next, determine the kinematic viscosity of lubricant.
3. Next, determine the kinematic viscosity of oil at 40C of 100.
4. Next, gather the formula from above = VI = (L-U) / (L-H).
5. Finally, calculate the Viscosity Index.
6. 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.

kinematic viscosity of oil at 40C of 0 = 68

kinematic viscosity of lubricant = 20

kinematic viscosity of oil at 40C of 100 = 3

VI = (L-U) / (L-H) =  ?