Ratio Calculator - Simplify, Solve & Scale Ratios Ratio Calculator

Use our free ratio calculator to simplify ratios, solve proportions, or scale ratios to a target value instantly.

Choose Mode

:

Your Results

Simplified Ratio 3 : 2
Working GCD(12, 8) = 4 → 12/4 : 8/4 = 3 : 2
Original Ratio 12 : 8
Simplified 3 : 2
As Fraction 3/2
As Decimal 1.5

Equivalent Ratios

MultiplierEquivalent Ratio

Ratio Calculator - Guide

What is a Ratio?

A ratio is a comparison between two or more quantities that shows their relative sizes. Ratios are written as A:B and can be simplified just like fractions. They are used extensively in cooking, construction, finance, map scales, and mixing proportions.

Ratio Formulas

1. Simplify a Ratio

Divide both parts by their GCD. E.g., 12:8 → GCD=4 → 3:2

2. Solve a Proportion (A:B = C:?)

? = (B × C) ÷ A

3. Scale a Ratio

Multiply both parts by the scale factor. E.g., 3:5 × 4 = 12:20

Examples

  • Simplify 15:25: GCD(15,25) = 5 → 3:5
  • Solve 2:3 = 10:? ? = (3 × 10) ÷ 2 = 15
  • Scale 4:7 by 3: 4×3 : 7×3 = 12:21
  • Ratio to fraction: 3:4 = 3/4 = 0.75

Common Uses of Ratios

  • Cooking: Recipe ingredient proportions (e.g., 2:1 water to rice).
  • Maps & Models: Scale ratios like 1:50000 for maps.
  • Finance: Debt-to-equity ratios, price-to-earnings ratios.
  • Mixing: Paint or chemical mixing proportions.
  • Design: Aspect ratios for screens (e.g., 16:9).

How This Calculator Works

  1. Choose a mode: “Simplify”, “Solve A:B = C:?”, or “Scale Ratio”.
  2. Enter values: Type your numbers into the input fields.
  3. Instant result: The simplified ratio, formula, and equivalent ratios update in real time.

Find a Calculator

Browse All Calculators →