Where these sizes come from
Each network publishes rules for what its tools accept: the shapes, file sizes and video lengths. The table follows the rules Karobar's publishing engine checks before it sends a post, which are taken from each network's own developer documentation. The "best size" is the common 1080-pixel-wide size for each shape, sharp on phones without being needlessly large.
The three shapes that cover almost everything
If you film and photograph with these three in mind, one shoot covers every network. Keep the product and any text inside the middle of the frame, because each app covers the top and bottom with buttons and captions.
- Vertical 9:16 (1080 × 1920): Reels, Stories, TikTok, YouTube Shorts and Facebook Reels.
- Portrait 4:5 (1080 × 1350): Instagram and Facebook feed posts and carousels. It takes up the most room in the feed.
- Landscape 16:9 (1920 × 1080): ordinary YouTube videos and many LinkedIn videos.
Rules that catch people out
- Instagram feed photos must be between 4:5 portrait and 1.91:1 landscape; anything taller is refused.
- Every slide in an Instagram carousel is cropped to the shape of the first one.
- A YouTube video counts as a Short only when it is vertical or square and up to three minutes long.
- TikTok photo posts are resized to fit 1080 × 1920, so wide photos get bars or crops.
- Facebook Reels need at least 540 × 960 pixels and 3 to 90 seconds.
Crop or fit?
Crop to fill when the subject sits in the middle and the edges do not matter. Fit with blurred edges when nothing may be cut off, such as a product with text on it or a group photo. It keeps the whole picture and fills the empty space with a blurred copy, so there are no black bars.
Planning a month of posts in these sizes? See How to build a social media content calendar.
Crop once, post everywhere
Karobar checks every photo and video against each network's rules before it posts, and its editor crops, fits with blurred edges, trims and picks covers for you. See Social Content.