Ratio Calculator

Simplify ratios, scale to a target, compare ratios, and convert to fractions or percentages. Includes aspect ratio presets.

Ratio

Enter a ratio to simplify.

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Percentages

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Formulae

Simplify A:B = divide both by GCD(A, B)

Scale A:B to A'=T → B' = T × B / A

A:B = C:D iff A × D = B × C (cross-multiplication)

Golden ratio φ = (1 + √5) / 2 ≈ 1.618034

1

Choose a mode

Select Simplify, Scale, Compare, or Aspect Ratio from the tabs.
2

Enter your ratio

Type the parts of the ratio (e.g. 15 and 25 for 15:25).
3

Read the result

The simplified ratio, scaled value, or comparison result appears instantly.

How do I simplify a ratio?

Divide both parts by their greatest common divisor. For example, 15:25 simplifies to 3:5.

What is the golden ratio?

The golden ratio (phi) is approximately 1.618. If a:b is in golden ratio, then a/b = phi.

Is my data sent anywhere?

No. All calculations run in your browser.

Work with ratios effortlessly. Simplify any ratio to its lowest terms,

scale a ratio to a target value, check if two ratios are equivalent,

and convert between ratios, fractions, decimals, and percentages.

Aspect ratio mode offers common presets (16:9, 4:3, etc.) and a golden

ratio calculator. Supports three-way ratios. All processing runs in

your browser.

Add, subtract, multiply, or divide fractions with step-by-step solutions. Simplify and convert between fractions, decimals, and percentages.

Calculate percentages instantly — find X% of Y, what percentage X is of Y, or the percentage change between two values.