Enter the resolution of the image in megapixels and the compression ratio to calculate the approximate image size in megabytes (MB).

Image Usage Formula

The following formula is used to calculate the image size.

IS = (R * 3) / CR


  • IS is the image size (MB)
  • R is the resolution of the image (megapixels)
  • CR is the compression ratio

To calculate the image size, multiply the resolution of the image by 3 (assuming 3 bytes per pixel as a standard for uncompressed RGB images) and then divide by the compression ratio.

What is Image Size?

Image size refers to the digital size of an image file, typically measured in megabytes (MB). It is determined by the resolution of the image, which is the number of pixels it contains, and the compression ratio, which reduces the file size by encoding the image data more efficiently. Understanding image size is important for managing storage space, especially when dealing with high-resolution photography or graphic design projects.

How to Calculate Image Size?

The following steps outline how to calculate the Image Size.

  1. First, determine the resolution of the image (R) in megapixels.
  2. Next, determine the compression ratio (CR).
  3. Next, gather the formula from above = IS = (R * 3) / CR.
  4. Finally, calculate the Image Size (IS) in megabytes (MB).
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

resolution of the image (R) = 12 megapixels

compression ratio (CR) = 4