Free Aspect Ratio Calculator
Calculate proportions, find missing dimensions, and simplify aspect ratios using physical resolutions
Aspect Ratio Calculator
Aspect Ratio: 16:9
Ratio: 1.7778
Width ÷ Height = 1.7778
GCD Simplified: 16:9
Calculate New Dimensions:
Common Aspect Ratios:
Understanding Aspect Ratios in Digital Media
An aspect ratio is the proportional relationship between the width and height of a digital image, screen, or design container. Expressed as two numbers separated by a colon (such as 16:9), it indicates that for every unit of width, there is a corresponding proportion of height, regardless of the physical size or hardware resolution.
How to Calculate Aspect Ratio (The GCD Formula)
To simplify any custom display resolution (e.g., 1920×1080) into its base aspect ratio, find the **Greatest Common Divisor (GCD)** between the width and height, and then divide both values by that divisor:
Base Width = Original Width ÷ GCD(Width, Height)
Base Height = Original Height ÷ GCD(Width, Height)
For a standard Full HD monitor of 1920 × 1080 pixels, the Greatest Common Divisor is 120:
Height: 1080 ÷ 120 = 9
Resulting Aspect Ratio = 16:9
Standard Aspect Ratios Reference Table
A handy guide to the most common aspect ratios used across screens, social platforms, and cinema formats:
| Ratio Spec | Decimal Factor | Common Application | Example Resolutions |
|---|---|---|---|
| 1:1 | 1.00 | Square (Instagram posts, profile avatars) | 1080 × 1080, 500 × 500 |
| 4:3 | 1.33 | Standard (Classic TV, iPad tablets, photography) | 1024 × 768, 1600 × 1200 |
| 16:9 | 1.78 | Widescreen (HD monitors, YouTube videos, presentation slides) | 1920 × 1080, 3840 × 2160 |
| 16:10 | 1.60 | Modern laptops (MacBook Pro standard, productivity screens) | 2560 × 1600, 1920 × 1200 |
| 21:9 | 2.33 | Ultrawide (Gaming monitors, cinematic formats) | 3440 × 1440, 2560 × 1080 |
| 9:16 | 0.56 | Portrait (Instagram Stories, TikTok videos, YouTube Shorts) | 1080 × 1920, 720 × 1280 |
Maintaining Proportions When Resizing
When scaling an element while keeping its exact aspect ratio intact, use these mathematical rules based on the original width ($W_1$) and height ($H_1$):
Calculating New Width: New Width = New Height × (W₁ ÷ H₁)
In modern web stylesheets, the native CSS aspect-ratio property simplifies layout sizing automatically:
width: 100%;
aspect-ratio: 16 / 9;
}
