Free Online Ratio Calculator

A ratio calculator simplifies comparing two quantities by reducing them to their lowest terms, converting between ratio formats, and showing proportional relationships. Whether you're scaling recipes, mixing chemicals, analyzing financial metrics, or solving math problems, this tool handles all ratio calculations instantly and accurately.

Enter any two values and the calculator finds the greatest common divisor (GCD), divides both numbers by it to create the simplest ratio, shows percentage equivalents, and provides scaling factors for proportions. Perfect for students, professionals, cooks, engineers, and anyone working with comparative measurements.

What is a Ratio?

A ratio compares two quantities, showing the relative size of one to the other. Expressed as "a:b" or "a to b," ratios maintain their value when both parts are multiplied or divided by the same number. The key is simplification—finding the smallest whole numbers that maintain the same relationship.

For example, 20 apples to 30 oranges is the ratio 20:30. Both numbers divisible by 10 (their GCD), so it simplifies to 2:3. This means "for every 2 apples, expect 3 oranges." The calculator automates finding this greatest common divisor and performing the division.

Ratios appear everywhere: cooking (2:1 flour to water), finance (debt:equity 1:2), design (3:2 aspect ratio), chemistry (1:1 acid:base), and sports (win:loss records). Understanding and simplifying ratios unlocks proportional thinking across disciplines.

How the Ratio Calculator Works

Greatest Common Divisor (GCD)

The calculator uses the Euclidean Algorithm to find the GCD—the largest number dividing both values without remainder. For 36:48, GCD=12, so 36÷12:48÷12 = 3:4.

Simplification Process

Percentage Conversion

Ratios convert to percentages: 3:4 = 3/(3+4) = 42.9% vs 57.1%. Useful for understanding part-to-whole relationships.

Scaling & Proportions

Scale 2:3 to total 50 parts? 2x+3x=50 → x=14.29 → 28.6:21.4. Calculator solves these instantly.

How to Use the Ratio Calculator

Step 1: Enter Two Values

Input quantity 1 and quantity 2. 150ml water : 300g flour = 150:300.

Step 2: Get Simplified Ratio

Instant result: 1:2. Shows GCD used (150) and steps taken.

Step 3: Percentage Breakdown

Water: 33.3%, Flour: 66.7% of total mixture.

Step 4: Scale to Total

Need 2kg total? Water: 667g, Flour: 1333g. Perfect proportions maintained.

Real-World Applications

Cooking & Baking

Double chocolate chip cookies? Original 2 cups flour:1 cup sugar → 4:2. Triple recipe? 6:3. Scale perfectly without guesswork.

Chemistry & Mixing

1:10 bleach:water disinfectant. Simplify 200ml:2L → 1:10. Scale to 5L bucket: 500ml:4.5L.

Finance & Business

Debt:Equity 3:2 → 60% debt financed. Revenue:Cost 5:3 → 62.5% gross margin.

Design & Architecture

Golden ratio 1:1.618. Screen aspect 16:9. Print layouts 2:3. Maintain perfect proportions.

Sports & Games

Batting average 3:10 → .300. Win:loss 7:3 → 70% win rate.

Practical Examples

Recipe Scaling: Pancakes

Concrete Mix: 1:2:3 (Cement:Sand:Gravel)

Small batch 100kg cement → 200kg sand, 300kg gravel. Large slab 1 ton cement → 2 tons sand, 3 tons gravel.

Website Traffic: 65%:35% (Organic:Paid)

10,000 visitors → 6500 organic, 3500 paid. 50,000 visitors → 32,500 organic, 17,500 paid.

Ratio Types & Formats

Part-to-Part vs Part-to-Whole

Boys:Girls 3:2 (part-to-part). Boys:Total 3:5, Girls:Total 2:5 (part-to-whole).

Equivalent Ratios

4:6 = 8:12 = 20:30 = 2:3. All represent same relationship.

Inverse Ratios

Speed:Time 2:1 → Time:Speed 1:2. Perfect reciprocals.

Frequently Asked Questions

What does "simplify ratio" mean?

Divide both numbers by their greatest common divisor (GCD) to get smallest whole numbers maintaining same proportion.

Can ratios have decimals?

Yes, but simplified ratios use whole numbers. 1.5:3.0 → 1:2 after ×2.

How do I scale a ratio?

Multiply both parts by same factor. 2:3 × 10 = 20:30. Calculator does math.

Ratio vs Fraction?

3:4 ratio = 3/4 fraction = 75% = 0.75 decimal. Different representations, same relationship.

Three-part ratios?

Cement:Sand:Gravel 1:2:3. Simplify by common divisor of all three numbers.

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Disclaimer

This ratio calculator provides accurate mathematical simplification and proportion calculations for educational, professional, and practical use.