Calculate enlargement ratio, percentage, print size from pixels and DPI, or copier scale between paper sizes for photos and posters.

Enlargement Ratio Calculator

Enlargement Ratio
Pixels ↔ Print Size
Copier Scale (Paper)

Enter Final Size and Initial Size to calculate the ratio, or enter a size and a ratio/percentage to calculate the other size.

Enlargement Ratio Formula

The following formula is used to calculate the Enlargement Ratio. 

ER = FS / IS
  • Where ER is the enlargement ratio (scale factor), unitless
  • FS is the final size (in the same units as IS)
  • IS is the initial size
  • Enlargement percentage (%) = ER × 100

To calculate an enlargement ratio, divide the final size by the initial size. To express the result as a percentage (as commonly used on copiers), multiply the ratio by 100.

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

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

ER = 25 / 10 = 2.5000 (ratio)

Enlargement percentage = ER × 100 = 250.00 (%)

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 = ?