Proportions Calculator home

Proportions Calculator is a simple tool for calculating proportions. Just enter any three values and the program will find the fourth. Use it for resizing images and videos, finding tip amounts, calculating sales tax, scaling recipes, converting currency, or anything where proportions are used.

Proportions Calculator screenshot


  • Any value can be the unknown
  • Each entry can be cleared individually
  • All entries can be cleared at one time
  • A and B entries can be swapped
  • The A/B and B/A divided results are shown
  • The reduced values for both ratios are shown
  • The color theme can be changed
Proportions Calculator features