Ratio Calculator
Simplify and compare ratios
Ratio Calculator
Simplify ratios, find missing values, calculate aspect ratios
Ratio Result
About Ratio Calculator
The Ratio Calculator helps you simplify ratios, find missing values in proportions, and calculate aspect ratios. Perfect for students, designers, photographers, and anyone working with proportions.
Whether you're scaling recipes, resizing images, or solving math problems, our calculator provides instant, accurate results.
How to Use This Ratio Calculator
Step 1: Select calculation type: Simplify, Find Missing, or Aspect Ratio.
Step 2: For Simplify: Enter 2 or 3 numbers to get the simplified ratio.
Step 3: For Missing: Enter a:b = c:x to find the missing value x.
Step 4: For Aspect: Enter width and height to get the aspect ratio.
Step 5: Click "Calculate" to see your results.
Step 6: Use the Reset button to clear all inputs and try different values.
Why Use a Ratio Calculator?
✓ Simplify Ratios
Reduce ratios to simplest form instantly. Perfect for math homework and everyday calculations.
✓ Find Missing Values
Solve proportions quickly. Great for recipe scaling, map distances, and financial ratios.
✓ Aspect Ratio
Calculate screen ratios, image dimensions, and video resolutions. Essential for designers and photographers.
✓ Multiple Modes
Three calculators in one. Simplify, find missing values, and calculate aspect ratios.
Real-World Applications of Ratios
- 📐Cooking & Baking: Scaling recipes up or down. 2:1 ratio of flour to water for bread.
- 📐Photography & Design: Aspect ratios for images (16:9, 4:3, 1:1). Maintaining proportions when resizing.
- 📐Finance: Financial ratios (debt-to-equity, price-to-earnings). Analyzing company performance.
- 📐Construction: Concrete mix ratios (1:2:4 for cement:sand:aggregate). Proportions in blueprints.
Ratio Formulas & Methods
Simplifying Ratios
Find GCD of all numbers, divide each by GCD. Example: 12:18 → GCD=6 → 2:3.
Cross Multiplication
a:b = c:x → x = (b × c) ÷ a. Example: 2:3 = 4:x → x = (3×4)÷2 = 6.
Common Ratio Examples
| Ratio | Use Case | Equivalent Ratios |
|---|---|---|
| 2:3 | Common for photography | 4:6, 6:9, 8:12 |
| 16:9 | Widescreen TV/Monitor | 32:18, 48:27, 64:36 |
| 4:3 | Standard TV/Old monitor | 8:6, 12:9, 16:12 |
| 1:1 | Square (Instagram) | 2:2, 3:3, 4:4 |
Frequently Asked Questions
Find the greatest common divisor (GCD) of both numbers and divide both by it. Example: 12:18 → GCD is 6 → 12÷6 = 2, 18÷6 = 3 → Simplified ratio = 2:3. Our calculator does this automatically for any ratio.
Find the GCD of all three numbers, then divide each by the GCD. Example: 6:9:12 → GCD is 3 → 6÷3=2, 9÷3=3, 12÷3=4 → Simplified ratio = 2:3:4.
Use cross multiplication. If a:b = c:x, then x = (b × c) ÷ a. Example: 2:3 = 4:x → x = (3 × 4) ÷ 2 = 6. Our calculator helps you find missing values in proportions.
Aspect ratio is the proportional relationship between width and height. Common ratios: 16:9 (widescreen), 4:3 (standard), 1:1 (square). Used for screens, images, and videos.
To convert a:b to percentage, use: (a ÷ (a+b)) × 100. Example: 2:3 → (2÷5) × 100 = 40% and 60%. Useful for understanding proportions in data and statistics.
A ratio compares two quantities (2:3). A proportion states that two ratios are equal (2:3 = 4:6). Proportions are used to find missing values. Our calculator handles both.
Divide the total by the sum of the ratio parts, then multiply by each part. Example: split $500 in a 2:3 ratio → sum = 5 parts → $500 ÷ 5 = $100 per part → $200 and $300. This is how bonuses, profit-sharing, and recipe scaling by ratio are usually worked out.
A common general-purpose mix is 1:2:4 (cement : sand : aggregate) by volume, though the right ratio depends on the structural requirement — foundations, slabs, and columns often call for stronger mixes like 1:1.5:3. Always follow the ratio specified by your structural engineer or local building code for load-bearing work.
Built and maintained by Sanjay Singh · Founder, Numrexo
Builds and maintains the calculators on Numrexo. Each tool's formula is documented on its page, and any reference source it relies on is listed under Method and references.
Last updated: · Calculations run in your browser. Nothing you enter is sent to us or stored.
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