Enter the total number of new cases of a disease and the total average population that could be exposed to the disease in the same time period to determine the incidence rate.

- Absolute Risk Reduction Calculator
- Relative Risk Calculator
- Number Needed to Treat Calculator (NNT)
- Attack Rate Calculator

## Incidence Rate Formula

The following formula is used to calculate an incidence rate.

IR = #NC / AP * 100

- Where IR is the incidence rate (%)
- #NC is the number of new cases during the time period
- AP is the average population during the time period

## Incidence Rate Definition

An incidence rate is a measure of the total number of people that contract a disease over a period of time compared with with people who could have been exposed to the disease.

## Incidence Rate Example

How to calculate incidence rate?

**First, determine the number of new cases.**In the specific time period being analyzed, determine the total number of new cases of the specific disease.

**Next, determine the average population.**Measure the average population that could be exposed to the disease during the same time period.

**Finally, calculate the incidence rate.**Enter the values from step 1 and 2 into the formula above to determine the incidence rate.

## FAQ

**What is an incidence rate?**

An incidence rate is a measure of the total number of people that contracted a disease over a period of time compared to the total number of people that could have been exposed to the disease.