Enter the total number of new cases of 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
- R0 Calculator
- Cumulative Incidence 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

To calculate an incidence rate, divide the number of new cases during the time period by the average population, then multiply by 100 to express the result as a percentage.

## 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 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 steps 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.