Aspect Ratio Calculator

What is an Aspect Ratio?

An aspect ratio is the proportional relationship between the width and height of an image or screen, expressed as two numbers separated by a colon (e.g., 16:9). It describes the shape of the rectangle and is crucial in photography, videography, and display technology.

Formula

The aspect ratio is calculated by finding the greatest common divisor (GCD) of the width and height, then dividing both dimensions by this value:

$$\text{Aspect Ratio} = \frac{\text{Width}}{\text{GCD}} : \frac{\text{Height}}{\text{GCD}}$$

Where GCD is the Greatest Common Divisor of the width and height.

How to Calculate Aspect Ratio

  1. Measure or obtain the width and height of your image or screen in pixels
  2. Find the GCD of these two numbers
  3. Divide both dimensions by the GCD
  4. Express the result as a ratio (width:height)

Example Calculation

Let's calculate the aspect ratio for a Full HD display:

Given:

  • Width = 1920 pixels
  • Height = 1080 pixels

Step 1: Find the GCD of 1920 and 1080

  • GCD(1920, 1080) = 120

Step 2: Divide both dimensions by the GCD

  • Width ratio = 1920 ÷ 120 = 16
  • Height ratio = 1080 ÷ 120 = 9

Result: The aspect ratio is 16:9

Common Aspect Ratios

  • 16:9 - Modern widescreen standard (HDTV, YouTube, most modern displays)
  • 4:3 - Traditional TV and computer monitors
  • 21:9 - Ultra-wide monitors
  • 1:1 - Square (Instagram posts)
  • 3:2 - Standard photography (35mm film)
  • 16:10 - Some laptop displays

Why Aspect Ratios Matter

  • Display Compatibility - Ensuring content fits screens properly without distortion
  • Content Creation - Designing graphics and videos for specific platforms
  • Photography - Choosing the right crop for prints and displays
  • Cinematography - Determining the visual style and composition of films

Real-World Applications

  • Video Production - Selecting the correct format for different platforms (YouTube, TikTok, Instagram)
  • Web Design - Creating responsive images that scale properly
  • Print Media - Sizing photos for frames and publications
  • Gaming - Optimizing game displays for different monitor types