Enter the insulation resistance after 10 minutes and the insulation resistance after 1 minute into the Calculator. The calculator will evaluate the Polarity Index.

## Polarity Index Formula

PI = R10 / R1

Variables:

- PI is the Polarity Index ()
- R10 is the insulation resistance after 10 minutes
- R1 is the insulation resistance after 1 minute

To calculate Polarity Index, divide the insulation resistance after 10 minutes by the resistance after 1 minute.

## How to Calculate Polarity Index?

The following steps outline how to calculate the Polarity Index.

- First, determine the insulation resistance after 10 minutes.
- Next, determine the insulation resistance after 1 minute.
- Next, gather the formula from above = PI = R10 / R1.
- Finally, calculate the Polarity 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.

insulation resistance after 10 minutes = 2.5

insulation resistance after 1 minute = 3