Pick Instagram, TikTok or YouTube on a post and you get a 1080×1920 export with every word clear of that app's own interface.
The canvas is the easy half. All three take 1080×1920, and that is where almost every size guide stops.
The half that costs you
Each app draws its own buttons on top of your image, and the three do it differently. Instagram puts a reply bar along the bottom. TikTok stacks a caption block and an action rail down the right. YouTube Shorts has its own arrangement again.
Design to the canvas and your call to action ends up underneath a reply bar. Design to the union of all three and one file posts everywhere without re-cropping — at the cost of a usable area that is, genuinely, smaller than a plain square post.
That is the actual constraint, and it is the reason this took longer than "add a new size".
The honest part about the numbers
No platform publishes an organic safe-zone spec. Not one.
The values we use are working values — what each interface actually covers, rounded outward so a rounding error lands in your favour rather than over your headline. There is exactly one published figure, it is Meta's, it is for ads, and it is far stricter than organic needs.
We keep those two apart rather than averaging them into a number that is wrong for both, and we say which is which at getpostpop.com/tools/safe-zone — a free checker that runs in your browser and never uploads your image.
The handles that had nowhere to go
Your TikTok and YouTube handles have been sitting in your brand kit for months with nothing to stamp them on. A field somebody filled in that changes nothing they can see is worse than no field. Now there is something.
And since this shipped, any carousel also exports as a video on the same canvas — same 1080×1920, same safe area, because the apps draw the same interface over a video that they draw over a still.