Aspect Ratio Calculator
Find the aspect ratio of any width × height, or enter a target ratio and one dimension to get the other. Includes one-tap presets for 16:9, 4:3, 1:1, 9:16 (Reels/TikTok) and 21:9.
16:9
Aspect ratio
1.778
Decimal ratio (w ÷ h)
How to use
- Enter a width and height to see the simplified ratio.
- Or pick a preset ratio and type one dimension — the other is calculated.
- Use it for video exports, thumbnails, prints and social posts.
Frequently asked questions
YouTube is 16:9 (1920×1080), Instagram Reels and TikTok are 9:16 (1080×1920), and square posts are 1:1 (1080×1080).
By dividing both sides by their greatest common divisor — so 1920×1080 becomes 16:9.