Vertical video format (9:16): dimensions, safe zones and export settings per platform

9:16: 1080 × 1920, and why it won

A 9:16 ratio is 16:9 standing up: 9 units wide for 16 high. At vertical 1080p that gives 1080 pixels wide by 1920 high, the screen of a phone held the normal way. YouTube reminds us that “the standard aspect ratio for YouTube on a computer is 16:9” and that a vertical video gets padding there: 9:16 is a format built for the phone, and only for it.

And the phone won. Médiamétrie, in its Internet Year 2025 report: “Mobile use is taking over in a big way; it accounts for 80% of time spent online (and more than 90% among 15- to 24-year-olds)”, with 48.6 million daily internet users in France and more than three hours a day online. Social networks and messaging take 39% of daily browsing, 61% among 15-to-24-year-olds. A short video is therefore watched on a vertical screen, held in one hand, with an interface laid over it.

The specs per platform

Safe zones: what is official, what is not

The safe zone is the part of the frame the interface does not cover: neither the caption and buttons at the bottom, nor the account name at the top, nor the column of icons on the right. No platform publishes a safe zone for organic videos; the only official templates are for ads, and they are already a good base.

• Google (vertical video ads on YouTube). On a 1080 × 1920 canvas, the safe zone leaves 288 pixels at the top, 672 at the bottom, 192 on the right and 48 on the left, an 840 × 960 pixel rectangle. Google warns: “Overlays, call-to-actions, and buttons may appear in different places depending on the format, campaign type, and screen”. There is no equivalent spec for organic Shorts.
• Meta (Reels ads). “Consider leaving at least 14% of the top, 35% of the bottom, and 6% on each side of your asset free from text, logos, or other important creative elements”. The help page adds to keep “the edges (top, bottom and sides) free of key creative elements”, and 40% at the bottom if the ad carries a disclaimer.
• TikTok. No pixels: “The safe zone size is determined by the dimension (vertical, horizontal, or square), ad caption length, and any additional formats used”, with downloadable templates. And the warning: “Elements that appear out of the safe zone might be covered or cropped”.
• Snapchat. “Keep the top 150px and the bottom 330px of your canvas clear” of any text or logo, one spec for Stories, Spotlight and Commercials.

These four templates say the same thing to within a few pixels: text and faces live in the central band, leaving about 15% at the top, 35% at the bottom and around ten percent on the right. That is what flysub’s preview shows when you turn the zones on: a 14% band at the top (Instagram profile zone), an 18% band at the bottom (Instagram actions zone) and a 12% column on the right (TikTok), so you can check at a glance that the subtitles stay readable once the interface sits on top.

Export settings

Two habits that avoid bad surprises: export at 1080 × 1920 even if you shot in 4K, because that is the definition platforms serve on mobile; and keep a constant frame rate from shoot to export, because a switch from 30 to 25 fps shows on camera moves.

Going from 16:9 to 9:16 without stretching

A horizontal video holds three times too much width for a vertical screen. Three ways to fit it in, none of which is stretching it.

• Crop on the face. Keep the central column around the person speaking. Ideal for an interview or a talking head; impossible when two people sit at the two edges of the frame.
• Split screen. Two people stacked, one on top, one below, each cropped on their face. It is the natural format of a two-person podcast or debate.
• Bars. The 16:9 video in the centre, with a blurred or plain background above and below. Acceptable for a wide shot or a screen, to be avoided on a face that becomes tiny.

flysub picks between the first two automatically: each clip is cropped on the person speaking, and switches to a split screen when two people talk. Subtitles sit by default between 65% and 78% of the height depending on the style, above the button area, and the preview shows the interface zones so you can check the result before export. The full walkthrough is in our guide to making Shorts from a long video.

Common mistakes

• Text in the bottom 35%. That is the caption and button area on every platform. Subtitles go above it.
• A stretched 16:9 video. Faces get longer and everyone can see it. Crop or switch to a split screen.
• An upscaled 720p export. Upscaling adds no detail; export at the definition you shot, capped at 1080 × 1920.
• Three empty opening seconds. That is when the thumb decides. flysub tolerates at most two seconds of silence in the first three seconds of a clip; beyond that, the clip starts at the next sentence.
• One file for every platform, without checking durations. A 3-minute clip works as a Short but not on X without a subscription (140 seconds).

For the readability of the subtitles themselves (number of lines, characters, speed), see our complete guide to video subtitles.