Enter the number of infections and the number of those at risk of infection into the Infection Rate Calculator. The calculator will evaluate the Infection Rate. 

Infection Rate Formula

The following two example problems outline the steps and information needed to calculate the Infection Rate.

IR = #I / #R * 100

  • Where IR is the Infection Rate (%)
  • #I is the number of infections 
  • #R is the number of those at risk of infection 

How to Calculate Infection Rate?

The following example problems outline how to calculate Infection Rate.

Example Problem #1:

  1. First, determine the number of infections. 
    • The number of infections is given as: 1,500.
  2. Next, determine the number of those at risk of infection. 
    • The number of those at risk of infection is provided as: 100,000.
  3. Finally, calculate the Infection Rate using the equation above: 

IR = #I / #R * 100

The values provided above are inserted into the equation below and computed.

IR = 1500 / 100,000 * 100 = 1.50 (%)


Example Problem #2: 

For this problem, the variables required are provided below:

number of infections = 2,000

number of those at risk of infection = 300,000

Test your knowledge using the equation and check your answer with the calculator..

IR = #I / #R * 100 = ?