---
title: "Ratio Calculator — Simplify, Scale & Solve Proportions"
description: "Simplify ratios (12:18 → 2:3), scale ratios, and solve proportions (a/b = c/d). Shows GCF and cross-multiplication. Free ratio calculator."
url: "https://worldcalculators.org/calculators/ratio/"
canonical: "https://worldcalculators.org/calculators/ratio/"
---

# Ratio Calculator

Simplify ratios (12:18 → 2:3), scale ratios, and solve proportions (a/b = c/d). Shows GCF and cross-multiplication. Free ratio calculator.

## Quick answer

To simplify : divide by GCF (12:18 → 2:3). To solve a:b = c:d : cross multiply (a×d = b×c). Scaling : multiply both parts by the same factor. Ratios are used in recipes, maps, scale models, and finance.

## Frequently Asked Questions

GCF(15, 25) = 5. Divide both: 15÷5 : 25÷5 = 3:5. The ratio 3:5 is equivalent to 15:25 in lowest terms.
A ratio compares two quantities (3:4). A proportion states that two ratios are equal (3:4 = 6:8). Solving a proportion finds a missing value using cross-multiplication.

Source: https://worldcalculators.org/calculators/ratio/
Markdown mirror of the HTML page. Prefer this URL for RAG; the interactive calculator still lives on the HTML page.