Explosion Tools

Ratio Calculator — Simplify & Solve Proportions

Simplify ratios to lowest terms and solve proportions. Find the missing value in A:B = C:?. Free, no signup, works in your browser.

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All calculations happen locally in your browser. No data is sent to any server.

About Ratio Calculator

This ratio calculator has two modes. In Simplify mode, enter any ratio (like 12:8) and the calculator reduces it to lowest terms (3:2) using the greatest common factor. It also shows the decimal and fraction equivalents. In Solve Proportion mode, enter three values of A:B = C:D and leave one blank — the calculator finds the missing value using cross-multiplication. Works with decimals and handles the math instantly in your browser. No data is sent to any server.

Frequently Asked Questions

How do you simplify a ratio?
Divide both numbers by their greatest common factor (GCF). For example, 12:8 → GCF is 4 → 3:2. The calculator does this automatically.
How do you solve a proportion?
Use cross-multiplication. For A:B = C:D, if D is unknown: D = (B × C) / A. Enter three values and leave one blank to solve.
Can I use decimals?
Yes. The calculator handles decimal ratios like 2.5:1.5 and simplifies them correctly by scaling to whole numbers first.

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