Type any width or height and get the matching dimension, simplified ratio, and platform-ready presets for TikTok, YouTube, Reels, Shorts and cinema.
| Platform | Ratio | Recommended export |
|---|---|---|
| TikTok, Reels, YouTube Shorts | 9:16 | 1080 × 1920 |
| YouTube standard | 16:9 | 1920 × 1080 or 3840 × 2160 |
| Instagram feed post | 4:5 | 1080 × 1350 |
| Square (feeds, ads) | 1:1 | 1080 × 1080 |
| Cinematic ultrawide | 21:9 | 2560 × 1080 |
| X / Twitter video | 16:9 or 1:1 | 1280 × 720 |
Generate in the ratio you'll publish in. Most AI video models (Seedance, Veo, Sora, Kling) support 16:9, 9:16 and 1:1 natively — generating at the target ratio beats cropping afterwards, because the model composes the shot for that frame.
Either re-generate at 9:16, or crop: a 1920×1080 clip yields a 608×1080 vertical slice, which upscales to 1080×1920. Expect to lose about two-thirds of the frame, so keep your subject centered.
Video encoders work in 2×2 pixel blocks, so always use even numbers — odd dimensions can break encoding or force re-scaling. This calculator rounds to whole pixels; keep them even for export.