Enter the incidence rate and the average duration of the condition into the calculator to determine the prevalence. This calculator helps in understanding the proportion of a population affected by a condition at a particular time.

## Incidence To Prevalence Formula

The following formula is used to calculate the prevalence from incidence rate and average duration of the condition.

P = I * D

Variables:

- P is the prevalence (per 1000 persons)
- I is the incidence rate (per 1000 person-years)
- D is the average duration of the condition (years)

To calculate the prevalence, multiply the incidence rate by the average duration of the condition.

## What is Prevalence?

Prevalence is a measure of the proportion of a population who have a specific characteristic in a given time period. In epidemiology, it is used to describe the proportion of people who have a particular disease or condition at a specific point in time or over a specified period. Prevalence helps public health officials understand the level of disease burden in a community and can inform healthcare planning and resource allocation.

## How to Calculate Prevalence from Incidence?

The following steps outline how to calculate the prevalence from incidence rate and average duration of the condition.

- First, determine the incidence rate (I) per 1000 person-years.
- Next, determine the average duration of the condition (D) in years.
- Next, gather the formula from above = P = I * D.
- Finally, calculate the prevalence (P) per 1000 persons.
- 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.

Incidence rate (I) = 5 per 1000 person-years

Average duration of the condition (D) = 8 years