Incidence Rate & Prevalence Calculator
Calculate disease prevalence (existing cases) and incidence rate (new cases over time) in a population. Essential epidemiological metrics for public health and disease surveillance.
Incidence Rate & Prevalence
basicCalculate disease prevalence and incidence rate
Formula
Prev = existing/pop, Inc = new/(pop × time)
How It Works
Prevalence measures how many people in a population have a disease at a specific point in time.
Incidence Rate measures how many NEW cases develop over a specific time period.
Prevalence (%) = Existing Cases / Total Population × 100
Incidence Rate = New Cases / Population × 100,000 / Years
Example
A city of 10,000 people has 500 existing diabetes cases and 100 new cases diagnosed this year:
Prevalence = 500/10,000 × 100 = 5.00%
Incidence Rate = 100/10,000 × 100,000/1 = 1,000 per 100K/year
Frequently Asked Questions
What is the difference between prevalence and incidence?
Prevalence = ALL existing cases (like a snapshot). Incidence = NEW cases over time (like a video). Prevalence depends on both incidence AND disease duration.
Why use per 100,000 for incidence?
Standardizing to per 100,000 allows comparison across populations of different sizes. This is the standard convention in epidemiology and public health reporting.