Aspect Ratio Calculator
Calculate image and video aspect ratios (16:9, 4:3, 1:1) and proportional scaling.
About Aspect Ratio Calculator
The Aspect Ratio Calculator calculates proportional image, video, and screen resolutions across standard aspect ratios (16:9 Widescreen, 4:3 Standard, 1:1 Square, 9:16 Vertical Video/Reels, 21:9 Ultrawide) with custom ratio scaling and CSS aspect-ratio export.
How to Use Aspect Ratio Calculator
Step 1
Enter original width (W₁) and height (H₁) or select a standard ratio preset (e.g. 16:9).
Step 2
Input your new desired width or height.
Step 3
The calculator instantly computes the missing dimension without distorting the image.
Step 4
Copy the calculated pixel dimensions or CSS aspect-ratio snippet.
Practical Use Cases for Aspect Ratio Calculator
Video Production & Social Media Formatting
Scale video resolutions between 16:9 YouTube landscape (1920x1080) and 9:16 TikTok/Instagram Reels vertical formats (1080x1920).
Web Responsive Layout & CSS Design
Calculate responsive iframe dimensions, image container padding ratios, and modern CSS aspect-ratio properties.
Input & Output Examples
Scaling 16:9 1080p Video to 720p Width (1280px)
Original: 1920x1080 (16:9), New Width: 1280px
Calculated Height: 720px | Aspect Ratio: 16:9 (1.7778) | CSS: aspect-ratio: 16 / 9;
Key Features & Performance
- ✓Calculates missing Width (W₂) or Height (H₂) maintaining exact proportional ratio.
- ✓Supports all standard aspect ratio presets: 16:9, 4:3, 1:1, 9:16, 21:9, 3:2, 5:4, 2.39:1.
- ✓Greatest Common Divisor (GCD) simplifier discovers exact integer ratio of any pixel dimensions.
- ✓Generates modern CSS `aspect-ratio` code snippets.
- ✓100% Client-Side calculation.
- ✓1-Click Copy dimension calculations.
Key Terminology & Definitions
Aspect Ratio
The proportional relationship between an image or display's width and height, commonly expressed as two numbers separated by a colon (x:y).
CSS aspect-ratio Property
A modern CSS property that allows web developers to define a preferred aspect ratio for any box element, automatically adjusting dimensions during responsive resizing.