Proportion solver

Solve a:b = c:x — fill three fields and find the missing fourth.

a : b = c : x — leave exactly one field blank.

Calculated in this browser. Nothing is sent anywhere.

Solves exact equality only; it does not round to whole units or know your domain (recipes, maps, currency). A zero result still requires the matching side to be nonzero.

How to use

  1. Enter three of the four positions.
  2. Leave the unknown one blank.
  3. Read the missing value and the scale.

What it supports

Solves exact equality only — it does not round to purchasable units or judge whether a proportion is the right model for your problem.

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