The Short Answer: 9:16 Is Dominant and You Should Default to It
If you're creating video for TikTok, Instagram Reels, or YouTube Shorts, shoot and export at 9:16 (1080 x 1920 pixels). This is the full-screen vertical format optimised for how people hold their phones. It takes up the entire screen. Anything else leaves black bars at the top and bottom, which looks unpolished and wastes screen real estate.
If you do nothing else from this article, remember this: 9:16 for short-form vertical content on every platform. That's the decision that affects your content most.
Platform by Platform
TikTok: 9:16 is the standard. TikTok also accepts 1:1 square and 16:9 horizontal, but both display with black bars in the feed. The full-screen experience on TikTok - no bars, content filling the whole display - only happens with 9:16. For any content intended for the For You Page, 9:16 is non-negotiable if you want it to look right.
Instagram Reels: 9:16, same as TikTok. Instagram displays Reels full-screen on mobile, and only 9:16 fills that space correctly. For regular feed posts (square or horizontal), 1:1 works well for photos and short clips. The 4:5 ratio (slightly taller than square) actually gets slightly more screen space in the feed and some creators prefer it for feed content specifically.
YouTube Shorts: 9:16. YouTube Shorts is built for the same vertical format. Uploading horizontal content to Shorts displays it with significant black bars and looks out of place in the Shorts feed.
YouTube long-form: 16:9 (1920 x 1080 or 3840 x 2160 for 4K). YouTube's player is horizontal and 16:9 fills it perfectly. Vertical videos uploaded to regular YouTube will have very large side bars on desktop and tablet viewing, which looks wrong for content intended to be consumed as a regular video rather than a Short.
Facebook: Mixed, depending on placement. Facebook Stories and Reels use 9:16. Regular feed posts perform well at 1:1 or 4:5, which take up more space in the mobile feed than 16:9. Facebook Watch content (longer videos) performs well at 16:9. If you're posting across Facebook placements without creating separate versions, 9:16 is the most compatible single choice.
X (Twitter): 16:9 for embedded video in the feed. Vertical video is supported but displays in a portrait frame with cropping on desktop. For X specifically, horizontal content tends to display more naturally across device types. If you're cross-posting content made for TikTok or Reels, the vertical format still works on X mobile.
LinkedIn: 1:1 or 4:5 for feed video. LinkedIn's audience is predominantly on desktop, making full vertical 9:16 less optimal than on consumer platforms. Square video takes up more space in the LinkedIn feed on both mobile and desktop, making it the most practical choice for professional content.
The Safe Zone Problem
Every platform has interface elements that overlay your video. TikTok has the like button, share button, caption, and username on the right side and bottom. Instagram Reels has similar overlays. This means a band of your 9:16 video is hidden behind UI elements.
The practical rule: keep important visual elements and text away from the bottom 20% and the right 15% of your vertical video. If you have a call to action, a person's face, or critical text near the bottom or right edge, it risks being obscured by the platform's own interface. Centre-heavy composition works most reliably across platforms.
Shooting for Multiple Formats at Once
If you shoot at 4K and need to deliver at multiple aspect ratios, shooting wider than necessary gives you crop flexibility in post. Shoot the subject roughly centred in the frame with some horizontal space on either side. In editing, you can then crop to 9:16, 1:1, or 16:9 without losing the subject. This workflow takes more thought during shooting but saves significant time compared to shooting separately for each format.
Some cameras and phones have "frame guides" that show multiple aspect ratios simultaneously in the viewfinder. Using these during shooting lets you see exactly where your 9:16 and 16:9 crops will fall at the same time.
What About Older Aspect Ratios - 4:3?
4:3 is the old television format and it basically doesn't belong on social media in 2026. If you're editing old footage that was shot in 4:3, pillarboxing it to 1:1 (adding horizontal black bars to make it square) is a better look than leaving it at its native aspect ratio, which will look dated. That said, for deliberately retro or nostalgic content, the old TV look is sometimes an intentional aesthetic choice.
For creating content to share across platforms, check the social media video settings guide for the full technical specifications per platform. And if you're downloading existing content to study how other creators compose their shots, MyVideoCity handles all major platforms.
Vertical Video on Desktop - The Viewing Experience Problem
Here's the thing nobody talks about: vertical video looks genuinely bad on desktop screens when viewed outside the platform's native player. A 9:16 video embedded in a website or opened in a media player on a 16:9 monitor has enormous black bars on either side. This is only an issue if your content gets shared or embedded outside the platform it was made for. If your content lives entirely on TikTok or Reels where the vertical player fills the screen, this doesn't matter.
For creators whose content gets syndicated, embedded in articles, or shared in contexts outside mobile social apps, having a horizontal version for those distribution contexts is worth considering. The extra edit takes a few minutes but serves a meaningfully different viewing context.
Pillarboxing and Letterboxing - What Those Terms Mean
Letterboxing is the black bars at the top and bottom of a horizontal video playing in a vertical space. Pillarboxing is the black bars on the sides of a vertical video in a horizontal space. Neither looks polished when avoidable. The way to avoid both is matching your content's aspect ratio to the context it's displayed in - which is why platform-specific export matters even when you're working from a single source file.