Enter the liquid limit, the natural moisture content, and the plasticity index into the Consistency Index Calculator. The calculator will evaluate the Consistency Index.

## Consistency Index Formula

The following formula is used to calculate the Consistency Index.

CI = (LL - NMC) / PI

Variables:

- CI is the Consistency Index ( )
- LL is the liquid limit
- NMC is the natural moisture content
- PI is the plasticity index

To calculate the consistency index, subtract the natural moisture content from the liquid limit, then divide by the plasticity index.

## How to Calculate Consistency Index?

The following steps outline how to calculate the Consistency Index.

- First, determine the liquid limit.
- Next, determine the natural moisture content.
- Next, determine the plasticity index.
- Next, gather the formula from above = CI = (LL – NMC) / PI.
- Finally, calculate the Consistency 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.

liquid limit = 10

natural moisture content = 5

plasticity index = 2

CI = (LL – NMC) / PI =** ** ?