Crop a video to 9:16, the vertical frame used by Shorts, Reels, TikTok, and Stories. A 1920x1080 source exports at 1080x1920.
The cost of cropping to 9:16
9:16 is the most destructive common crop. The tallest 9:16 rectangle that fits inside a 16:9 frame is 608x1080, so cropping keeps 32% of the original width and throws the rest away.
That is the right trade when one subject sits near the middle of the frame: a talking head, a single product, a phone screen recording. Drag the box left or right to follow whoever is speaking.
It is the wrong trade for a wide shot, a two-person interview, or anything where the edges carry the composition.
Fit instead of crop
Frame mode set to Fit with bars keeps all 1920 columns. The picture lands 1080x608 across the middle of a 1080x1920 frame and 656 px of background fills the space above and below it.
A blurred copy of the frame is the common choice for the bars. Black is the conventional letterbox. White reads better for screen recordings of documents and light interfaces.
Safe areas
Platform interface elements sit over the top and bottom of a 9:16 clip: captions, the username, the action rail. Keep anything that must stay legible inside the middle 60% of the height, which is roughly 384 px to 1536 px on a 1080x1920 export.