Ratio Calculator

1. 01Enter the two valuesType the first value (A) and the second value (B) of the ratio.
2. 02Read the simplified ratioThe simplified ratio, decimal, and percent update automatically as you type.

• Checking math homeworkQuickly simplify a ratio to its lowest terms and verify the answer.
• Scaling a recipe or mixSimplify an ingredient or mixing ratio (for example, 8:12 paint-to-thinner) to see the smallest whole-number version.
• Comparing two quantitiesTurn two raw numbers into a clean ratio to compare them, for example comparing screen widths or team sizes.

• Simplifying 12:1812:18 simplifies to 2:3 (both divided by their GCD, 6).
• A ratio already in lowest terms3:4 stays 3:4, since 3 and 4 share no common factor besides 1.
• Equal values5:5 simplifies to 1:1.

A ratio A:B is simplified by dividing both A and B by their greatest common divisor (GCD), found with the Euclidean algorithm. The result is the smallest whole-number pair that represents the same proportion. The tool also shows A ÷ B as a decimal and as a percentage, since a ratio and a fraction describe the same relationship in different notations.

You enter two positive whole numbers, A and B. The tool returns the simplified ratio A:B, the decimal value of A ÷ B, and that value as a percentage. Both inputs must be whole numbers greater than zero — a ratio is conventionally defined between positive quantities.

This calculator simplifies a single two-part ratio (A:B). It does not currently support a three-part ratio (A:B:C) or solving for a missing value in a proportion (A:B = C:x). A common mistake is entering decimal values — round or rescale them to whole numbers first (for example, 2.5:5 becomes 5:10, which simplifies to 1:2).

The calculation runs in your browser. The numbers you enter are never uploaded, stored, or shared, and closing the tab clears everything.

How do I simplify a ratio?

Divide both numbers by their greatest common divisor (GCD). For example, 12:18 has a GCD of 6, so it simplifies to 2:3.

What does a ratio mean as a percentage?

A ratio A:B expressed as A ÷ B, then multiplied by 100, gives its percentage form. A 1:4 ratio is 25%.

Can I enter decimal numbers?

Not directly — this calculator works with whole numbers. Rescale a decimal ratio to whole numbers first (multiply both sides until both are whole), then enter those.

Does it support three-part ratios like A:B:C?

Not currently — this tool simplifies a two-part ratio, A:B.

Is my data saved?

No. Everything is calculated in your browser; nothing is sent to a server.