Aspect Ratio Finder
General Aspect Ratio

How do I calculate aspect ratio from width and height?

Calculating aspect ratio from width and height is a simple mathematical process. Here's exactly how to do it:

The Formula:

Aspect Ratio = Width : Height (simplified to lowest terms)

Step-by-Step Manual Calculation:

Example 1: 1920 x 1080

  1. Start with your dimensions: Width = 1920, Height = 1080
  1. Find the Greatest Common Divisor (GCD)
    • List factors of 1920: ..., 120, 240, 480, 960, 1920
    • List factors of 1080: ..., 120, 180, 270, 540, 1080
    • GCD = 120 (largest number that divides both)
  1. Divide both dimensions by the GCD
    • 1920 ÷ 120 = 16
    • 1080 ÷ 120 = 9
  1. Result: 16:9 aspect ratio

Example 2: 1280 x 720

  1. Dimensions: 1280 x 720
  2. GCD: 80
  3. Divide: 1280 ÷ 80 = 16, 720 ÷ 80 = 9
  4. Result: 16:9

Quick Method Using Decimal:

  1. Divide width by height: 1920 ÷ 1080 = 1.777...
  1. Identify common ratios by decimal:
    • 1.33 = 4:3
    • 1.5 = 3:2
    • 1.6 = 16:10
    • 1.78 = 16:9
    • 1.85 = 1.85:1 (cinema)
    • 2.0 = 2:1
    • 2.35-2.40 = 2.39:1 (widescreen cinema)
  1. Round to recognize the ratio

Using Our Calculator (Easiest Method):

No math needed:

  1. Enter width: 1920
  2. Enter height: 1080
  3. Instantly get: 16:9

Common Dimension Examples:

DimensionsCalculationAspect Ratio
1920 x 10801920÷108016:9
2560 x 14402560÷144016:9
3840 x 21603840÷216016:9
1280 x 7201280÷72016:9
1024 x 7681024÷7684:3
3000 x 20003000÷20003:2
3440 x 14403440÷144021:9
1080 x 19201080÷19209:16

For Non-Standard Dimensions:

If your calculation results in unusual numbers (like 17.2:9), you might have:

  • An uncommon custom aspect ratio
  • Dimensions that include padding/borders
  • A need to round to the nearest standard ratio

Pro Tips:

  • ✅Always use the same units for width and height
  • ✅Calculator tools eliminate manual math errors
  • ✅Decimal format (1.78:1) is easier for quick comparisons
  • ✅Most content uses standard ratios (16:9, 4:3, 3:2)

Why This Matters:

Knowing how to calculate aspect ratio from width and height helps you:

  • Verify if content matches platform requirements
  • Resize images proportionally
  • Choose appropriate export settings
  • Understand camera and display specifications

For instant results without manual calculation, click here to use our aspect ratio calculator.

Related Resources

Back to All FAQs

Ready to Calculate Aspect Ratios?

Use our free aspect ratio calculator to find the perfect dimensions for your project.

Try the Calculator