Enter the frequency of the first phenotype and the frequency of the smallest phenotype into the Phenotypic Ratio Calculator. The calculator will evaluate and display the Phenotypic Ratio. 

Phenotypic Ratio Formula

The following formula is used to calculate the Phenotypic Ratio. 

PHR = F1 / FS

  • Where PHF is the Phenotypic Ratio ( )
  • F1 is the frequency of the first phenotype 
  • FS is the frequency of the smallest phenotype 

How to Calculate Phenotypic Ratio?

The following example problems outline how to calculate Phenotypic Ratio.

Example Problem #1:

  1. First, determine the frequency of the first phenotype. 
    • The frequency of the first phenotype is given as: 15.
  2. Next, determine the frequency of the smallest phenotype. 
    • The frequency of the smallest phenotype is provided as: 5.
  3. Finally, calculate the Phenotypic Ratio using the equation above: 

PHR = F1 / FS

The values given above are inserted into the equation below and the solution is calculated:

PHR = 15 / 5 = 3 ( )


Example Problem #2: 

For this problem, the variables required are provided below:

frequency of the first phenotype = 16

frequency of the smallest phenotype = 6

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

PHR = F1 / FS = ?