Enter the plastic limit and the liquid limit into the Plasticity Index Calculator. The calculator will evaluate the Plasticity Index.

## Plasticity Index Formula

The following two example problems outline the steps and information needed to calculate the Plasticity Index.

**PI = PL – LL**

Variables:

- PI is the Plasticity Index ( )
- PL is the plastic limit
- LL is the liquid limit

## How to Calculate Plasticity Index?

The following steps outline how to calculate the Plasticity Index.

- First, determine the plastic limit.
- Next, determine the liquid limit.
- Next, gather the formula from above = PI = PL – LL.
- Finally, calculate the Plasticity Index.
- 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.

plastic limit = 6

liquid limit = 4

PI = PL – LL** **= ?