Enter the total number of cases and the total population into the calculator to determine the prevalence of a disease. This calculator can also determine the number of cases or population size if provided the other variables.

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## Prevalence Formula

The following formula is used to calculate the prevalence rate of a disease.

P() = TC / TP *100

- Where P() is the prevalence rate (%)
- TC is the total number of cases
- TP is the total population size

To calculate prevalence, divide the number of cases by the population size, then multiply the result by 100.

## Prevalence Definition

Prevalence is defined as the portion or percentage of a population that has contracted a certain disease.

## Prevalence Example

How to calculate prevalence?

**First, determine the total number of cases.**Measure and determine the total number of people infected. For this example, we will say this number is 25.

**Next, determine the total population size.**For this example we will say the population size is 100 people.

**Finally, calculate the prevalence.**Using the formula above we find the prevalence is 25/100 * 100 = 25%.

## FAQ

**What is prevalence?**

Prevalence is a term most often used in medicine to describe what portion of a population has a certain disease. It can however be used in any other science to describe the rate of something occurring compared to a total number of events.