Aspect Ratio Calculator: 16:9, 4:3, 1:1 and Custom Sizes
Find the aspect ratio of any size, or calculate a missing width or height for 16:9, 4:3, 1:1 and more.
Open the free Aspect Ratio Calculator →What is the Aspect Ratio Calculator?
Find the aspect ratio of any size, or calculate a missing width or height for 16:9, 4:3, 1:1, 9:16 and more. It's completely free, needs no sign-up and works on any phone or computer.
Why it's helpful
- Find or keep any ratio
- Common video and photo presets
- Avoid stretched images
Who it's for
Video editors, designers and developers.
How to use it
- Enter a size to see its ratio, or pick a ratio to calculate a matching width or height.
💻 Open source: this tool is free and open source (MIT License). View the code on GitHub, download it and run it offline.
The bigger picture: Design
Good design builds trust in seconds. Colour, typography, spacing and accessibility tools help developers and small businesses create websites that look professional without hiring a full design team.
What's changing: Accessibility is moving from nice-to-have to expected, and modern CSS now does with a few lines what used to need images and JavaScript.
Frequently asked questions
Which ratio for social video?
9:16 for Reels, TikTok and Shorts; 16:9 for YouTube; 4:5 for Instagram feed posts.
