Why 9:16 matters
TikTok, Instagram Reels and YouTube Shorts are all 9:16: 1080 pixels wide and 1920 tall. Post a horizontal photo and the app either crops it hard or adds black bars. A blurred copy of the same photo behind it fills the screen and keeps the whole picture visible.
It matters even more for AI video. When you animate a photo, the video keeps the photo’s shape, so a vertical photo gives you a vertical video that fills the phone.
Which size for which platform
| Where | Shape | Export size |
|---|---|---|
| TikTok, Reels, Shorts, Stories | 9:16 | 1080 × 1920 |
| Instagram feed post | 4:5 | 1080 × 1350 |
| Square post or profile | 1:1 | 1080 × 1080 |
| YouTube, X, websites | 16:9 | 1920 × 1080 |
Tips for a clean result
- Keep faces in the middle third. The top and bottom of a vertical video are covered by captions and buttons. Check with the safe zone checker.
- Got an iPhone HEIC photo that will not open elsewhere? This tool reads HEIC, or convert a batch with the HEIC to JPG converter.
- Rather generate a vertical photo from scratch? Ask for a 9:16 composition with the Nano Banana prompt generator.