ReelAspect ratio calculator for video: 16:9, 9:16 and more
Enter a width and a height to get the aspect ratio, or pick a ratio and one side to get the other. A YouTube Short or TikTok is 9:16, which is 1080 × 1920 pixels; a normal YouTube video is 16:9, which is 1920 × 1080.
Common video sizes
| Use | Ratio | Pixels |
|---|---|---|
| YouTube Shorts, TikTok, Reels | 9:16 | 1080 × 1920 |
| YouTube video (HD) | 16:9 | 1920 × 1080 |
| YouTube video (4K) | 16:9 | 3840 × 2160 |
| YouTube thumbnail | 16:9 | at least 640 px wide; 1280 × 720 is common, YouTube suggests as large as 3840 × 2160 |
| Instagram feed, portrait | 4:5 | 1080 × 1350 |
| Square post | 1:1 | 1080 × 1080 |
Thumbnail sizes from YouTube Help, checked 30 October 2026.
9:16 or 16:9 for Shorts?
YouTube counts a video as a Short when it is square or vertical and three minutes or shorter (YouTube Help, checked 30 October 2026). A 16:9 upload counts as a normal video. On a phone, 9:16 fills the whole screen; a 16:9 film placed in a 9:16 frame leaves bars and wastes most of it.
If you make both, lay out the vertical version separately rather than cropping the wide one. Keep the subject in the middle third and keep text away from the top and bottom, where the app puts its buttons. 41 ReelStyles styles have a vertical layout built in, so your coding agent can animate a proper 9:16 film. See how to make 9:16 Shorts with Claude Code.
Make the video itself
ReelStyles is a set of 121 finished film styles for AI coding agents like Claude Code, Codex and Cursor, and 41 of them are made for 9:16. Your agent animates the whole film in code on your computer. 6 of the styles are free.
See the 121 styles Get 6 styles free
More free tools: all tools.