Aspect Ratio Calculator
Aspect Ratio
CSS aspect-ratio
Decimal
Resize Calculator
Result
Result
How to Use
Enter width and height to calculate the aspect ratio. Use the presets to quickly fill in common ratios like 16:9 or 4:3. The resize calculator lets you find new dimensions that maintain the same proportions.
Aspect Ratios Explained
An aspect ratio describes the proportional relationship between width and height. 16:9 is the standard for HD/4K video and most monitors. 4:3 was the classic TV and early computer standard. 21:9 is used for ultrawide displays and cinema. 1:1 is square, common in social media. 9:16 is vertical video for mobile platforms like TikTok and Instagram Reels.
Privacy
All calculations happen entirely in your browser. No data is sent to a server, stored, or logged.