Aspect Ratio Calculator
Calculate aspect ratios and proportional dimensions for images, videos, and screens. Lock W:H, find missing dimension. Runs in your browser.
Common presets Lock
:
Result
--
Reference
What is an aspect ratio?
An aspect ratio is the proportional relationship between width and height, written W:H. 16:9 is the standard for HDTV and YouTube; 4:3 is older TV/CCTV; 1:1 is square (Instagram); 21:9 is ultrawide; 9:16 is vertical (TikTok, Stories). The tool computes the GCD to simplify any W:H pair.
Common uses
- Video editing — match output to platform requirements.
- Web design — size hero images and embeds.
- Photography — crop to gallery or print sizes.
- App UI — design responsive image placeholders.
Privacy
All calculations run 100% in your browser. No data is sent to any server.