Ratio Calculator

Simplify ratios, scale them up or down, and find a missing value in a proportion.

Simplified Ratio

2 : 3

Why Use Our Ratio Calculator?

Three Calculation Modes

Simplify a ratio, scale it by a multiplier, or find a missing value in a proportion - all in one tool.

Auto-Simplification

The simplify mode reduces any ratio to its lowest terms using the greatest common divisor automatically.

Scale Any Ratio

Enter a ratio and a multiplier to instantly see the scaled version. Useful for recipes, maps, and engineering plans.

Solve Proportions

The missing value mode solves A:B = C:? so you can find unknown values in proportional relationships.

Instant Results

Results update as you type with no button to press. Switch between modes without losing your inputs.

100% Private

All calculation happens in your browser. No data is sent to any server.

Frequently Asked Questions

How do I simplify a ratio?

Select the Simplify tab, enter A and B, and the calculator reduces the ratio to its lowest terms automatically.

How do I scale a ratio?

Select the Scale tab, enter your base ratio A:B and a multiplier. The scaled ratio is calculated instantly.

How do I find a missing value in a proportion?

Select the Find Missing tab and enter A, B, and C to solve A:B = C:?. The missing fourth value is calculated and displayed.

What is a ratio used for?

Ratios are used in cooking (scaling recipes), maps (scale factors), finance (financial ratios), and many other fields where two quantities are compared.

Can I use decimal numbers in a ratio?

Yes. The ratio calculator accepts decimal inputs in all fields. Results are shown with appropriate decimal precision.

Is the ratio calculator free?

Yes. Completely free with no sign-up required.

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