Instagram post (portrait) size

What aspect ratio is 1080 x 1350?

1080 by 1350 is a 4:5 aspect ratio. Divide both numbers by their greatest common divisor, 270, and you get 4 by 5. As a decimal the frame is 0.8 wide for every 1 unit of height, and it is 1.25 times taller than it is wide.

For years 4:5 was also the tallest ratio Instagram would accept for a single feed image, and most guides still say so. That stopped being true on 29 May 2025, when Instagram head Adam Mosseri announced native support for 3:4 photos, the ratio almost every phone camera defaults to, for single posts and carousels. 3:4 at 1080 wide is 1080 by 1440, and it is now the tallest a single feed image goes. Anything taller than that, a 9:16 vertical for example, still gets cropped back rather than shown in full.

If you are working the other way round and know the ratio but not the pixels, 4:5 at 1080 wide is 1080 by 1350, at 2160 wide it is 2160 by 2700, and at 720 wide it is 720 by 900. Instagram will resample all of them to 1080 wide, so there is no benefit to exporting bigger.

Should I post 4:5 or the new 3:4?

Both are shown in full in the feed, and 3:4 is 90 pixels taller at the same 1080 width, so it takes slightly more of the screen. That alone is a thin reason to switch. The real one is the profile grid.

Instagram's profile tiles are 3:4. A 4:5 upload is wider than that tile, so the grid fills the tile by height and trims the sides: 1350 multiplied by 3/4 is 1012.5, which means about 34 pixels disappear off each edge. A 3:4 upload is already the exact shape of the tile, so it is cropped by nothing. Zero pixels. It is the only feed ratio where the image in the feed and the image on your profile are the same picture.

So the rule is simple. If the layout has anything living near the left or right edge, a logo, a price, the first and last letters of a wide headline, export 1080 by 1440 and the grid stops eating it. If you are reusing one export across Instagram, Threads and a Facebook post, stay on 4:5, because 3:4 is an Instagram-side change and the 4:5 file remains the safer traveller.

What gets cropped in the feed versus the profile grid?

Nothing is cropped in the feed. A 1080 by 1350 upload is exactly the frame Instagram renders as people scroll, which is the whole reason 4:5 is the recommended size.

The profile grid is where the crop happens, and this changed. Instagram moved profile tiles from a 1:1 square to a 3:4 portrait preview in early 2025, a change Instagram head Adam Mosseri explained by pointing out that most uploads are now vertical. Because 4:5 (0.8) is slightly wider than 3:4 (0.75), the grid fills the tile by height and trims the sides: 1350 multiplied by 3/4 is 1012.5, so roughly 1013 of your 1080 pixels remain and about 34 pixels disappear from each edge.

That is a small trim, but it is enough to clip a logo pinned to a corner or the first and last letter of a wide headline. A square 1080 by 1080 post fares much worse in the same 3:4 tile: it is far wider than the cell, so it loses about 135 pixels from each side.

There is now a way to avoid the trim entirely. Since Instagram added 3:4 feed support in May 2025 you can upload 1080 by 1440, which is the tile's own ratio, and the grid crops nothing off it. Almost every size guide still tells you 4:5 is as tall as the feed goes and then complains about the grid crop, without noticing that the fix shipped over a year ago.

Why does my post look different in the Instagram preview than after posting?

The composer preview and the posted result are two different crops of the same file. In the composer Instagram defaults to a centred crop of whatever ratio it thinks fits, and you have to tap the expand control to keep your full 4:5 frame. If you skip that step on a taller source image, Instagram picks the crop for you.

The second surprise comes later, on your own profile, because the grid re-crops to 3:4 as described above. A layout that looked balanced in the composer can end up with its edges shaved in the grid.

The fix is to design once at 1080 by 1350 and treat the middle 1013 pixels of the width as your safe zone. Then the feed shows everything, the grid tile shows everything that matters, and you never have to guess what the app decided to keep.

What changes between a post, a Story, a Reel and a profile picture?

A feed post is 1080 by 1350 at 4:5, and it is the only one of the four where the whole frame is visible with no interface sitting on top of it. Stories and Reels share a taller 1080 by 1920 at 9:16, so a post exported for the feed will be letterboxed or cropped if you push it into a Story.

Stories and Reels also lose usable space to the interface rather than to a crop. On a Story the profile ring and close control sit over the top of the frame and the reply bar sits over the bottom, roughly 250 pixels at each end. On a Reel the right-hand action buttons and the caption block cover the bottom third and the right edge.

A profile picture is a different shape again: a square upload, stored at about 320 by 320, always displayed inside a circle, and shown as small as 32 pixels beside your posts. So the four assets need three separate exports, and only the post and the carousel can share one file.