Enter the final size and the initial size into the Enlargement Ratio Calculator. The calculator will evaluate and display the Enlargement Ratio. 

Enlargement Ratio Formula

The following formula is used to calculate the Enlargement Ratio. 

ER = (FS – IS) / IS *100

  • Where ER is the Enlargement Ratio (%)
  • FS is the final size 
  • IS is the initial size 

How to Calculate Enlargement Ratio?

The following example problems outline how to calculate Enlargement Ratio.

Example Problem #1:

  1. First, determine the final size. 
    • The final size is given as: 25.
  2. Next, determine the initial size. 
    • The initial size is provided as: 10.
  3. Finally, calculate the Enlargement Ratio using the equation above: 

ER = (FS – IS) / IS *100

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

ER = (25 – 10) / 10 *100 = 150.00 (%)


Example Problem #2: 

For this problem, the variables required are provided below:

final size = 60

initial size = 30

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

ER = (FS – IS) / IS *100 = ?