Enter the nominal r-value and the percent decrease in performance (%) into the Calculator. The calculator will evaluate the Effective R-Value.

## Effective R-Value Formula

ER = NV * PD/100

Variables:

- ER is the Effective R-Value ()
- NV is the nominal r-value
- PD is the percent decrease in performance (%)

To calculate the Effective R-Value, multiply the nominal r-value by the percent decrease in performance over 100.

## How to Calculate Effective R-Value?

The following steps outline how to calculate the Effective R-Value.

- First, determine the nominal r-value.
- Next, determine the percent decrease in performance (%).
- Next, gather the formula from above = ER = NV * PD/100.
- Finally, calculate the Effective R-Value.
- 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.

nominal r-value = 2.25

percent decrease in performance (%) = 3