How is a ratio different from a fraction?

A ratio compares two (or more) quantities to each other (like 2 cups flour : 1 cup sugar), while a fraction represents a part of a single whole — but they're simplified the same mathematical way.

What is a proportion?

A proportion states that two ratios are equal (A:B = C:D) — this is commonly used to scale recipes, maps, or mixtures up or down while keeping the same relationship between quantities.

Ratio Calculator

Simplify any ratio to its lowest terms, or solve for a missing value in an equivalent ratio (A:B = C:?).

Mode

Simplified Ratio

2 : 3

How It Works

Simplifying a ratio

A ratio is simplified by dividing both sides by their greatest common divisor — the same technique used for simplifying fractions.

Solving a proportion

For equivalent ratios A:B = C:D, if three values are known, the fourth can be found by cross-multiplying: D = (B × C) ÷ A.

Example Calculation

The ratio 8:12 simplifies to 2:3. For the proportion 2:3 = 10:?, the missing value is (3 × 10) ÷ 2 = 15.

Common Mistakes

Simplifying only one side of a ratio instead of dividing both sides by the same number.
Mixing up which value corresponds to which position when solving a proportion — order matters (A:B must match C:D's order).

Frequently Asked Questions

How is a ratio different from a fraction?: A ratio compares two (or more) quantities to each other (like 2 cups flour : 1 cup sugar), while a fraction represents a part of a single whole — but they're simplified the same mathematical way.
What is a proportion?: A proportion states that two ratios are equal (A:B = C:D) — this is commonly used to scale recipes, maps, or mixtures up or down while keeping the same relationship between quantities.