Ratio Calculator – Aplicativy.

Simplify any ratio to lowest terms, or solve a proportion (a : b = c : ?) for the missing number.

Working with ratios and proportions

A ratio compares two quantities, and simplifying it to lowest terms makes the relationship easy to read. Sixteen to nine and thirty two to eighteen describe the same shape, but the simpler form is the one people recognize, as anyone who has chosen a screen knows.

A proportion sets two ratios equal and lets you solve for a missing value. This is the engine behind scaling a recipe, reading a map, mixing a solution, or converting between units, and it is one of the most widely used pieces of practical math.

Use the simplifier to reduce a ratio you already have, and the proportion solver when three of the four numbers are known and you need the fourth.

The formula

simplified: divide both terms by their greatest common divisor proportion: ? = c x b / a

Worked example

16 : 9 stays 16 : 9 (already lowest terms). For 3 : 4 = 9 : ?, the answer is 9 x 4 / 3 = 12.

How to read your result

Equivalent ratios scale by the same factor on both sides. Use the proportion solver for recipe scaling, maps, and mixing problems.

Frequently asked questions

What is a proportion?: A statement that two ratios are equal, which lets you solve for one unknown term.
Can ratios have decimals?: Yes, though whole-number ratios are usually clearer once simplified.
How do I scale a recipe?: Set up old : new for one ingredient and solve the proportion for the others.

Related calculators

Roxish — free, formula-transparent calculators for school, work, and everyday decisions.