Enter the number of false positives and the number of tests into the False Positive Rate Calculator. The calculator will evaluate the False Positive Rate. 

False Positive Rate Formula

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

FPR = FP / T * 100
  • Where FPR is the False Positive Rate (%)
  • FR is the number of false positives 
  • #T is the number of tests 

To calculate the false positive rate, divide the number of false positives by the number of tests, then multiply by 100.

How to Calculate False Positive Rate?

The following example problems outline how to calculate False Positive Rate.

Example Problem #1:

  1. First, determine the number of false positives.
    • The number of false positives is given as: 50.
  2. Next, determine the number of tests.
    • The number of tests is provided as: 150.
  3. Finally, calculate the False Positive Rate using the equation above: 

FPR = FP / #T * 100

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

FPR = 50 / 150 * 100 = 33.33 (%)

Example Problem #2: 

For this problem, the variables required are provided below:

number of false positives = 60

number of tests = 180

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

FPR = FP / #T * 100 = ?