Instagram Post Size — Free, Fast & Private
For most of Instagram's history the safe advice was simple: post 4:5 portrait, 1080×1350, and you get the most screen you are allowed. That advice needs an update. Instagram's profile grid has moved from square tiles to portrait tiles, and the ratio those tiles use is 3:4 — which makes 1080×1440 the shape that fills a grid cell edge-to-edge with no trimming. The platform now supports feed images anywhere in the range from 1.91:1 landscape to 3:4 portrait, so nothing about the older shapes broke: 4:5 posts still display cleanly in the feed, and squares are still accepted exactly as they always were. What changed is which shape is native to the profile page, and that is worth knowing before you crop.
3:4 or 4:5 — how to actually choose
The two portrait ratios are close enough that the difference sounds academic, but they behave differently in one place: the grid. A 1080×1440 image at 3:4 is the exact shape of a grid tile, so your profile shows the frame as you composed it. A 1080×1350 image at 4:5 is slightly shorter than the tile, so the grid preview trims a sliver to fill the cell — usually invisible, occasionally enough to clip a forehead or a caption near the edge. In the scrolling feed itself, both render fully. So: if the profile grid matters to you — portfolios, shops, anyone whose grid is a storefront — compose at 3:4. If you batch-produce content in 4:5 templates, there is no urgent reason to rebuild them; just keep critical elements away from the very top and bottom of the frame.
The ratio range is a hard boundary
Instagram accepts feed images between 1.91:1 (wide landscape) and 3:4 (tall portrait). Upload anything outside that window and the app forces a crop at posting time, on a phone screen, with your thumb — which is how group photos lose the person on the end and screenshots lose their punchline. A full-height 9:16 phone photo is the classic casualty: it is taller than 3:4, so something has to go. Deciding that crop yourself, at leisure, on the full image is strictly better than deciding it in the upload sheet. That is the point of the ratio chips in the cropper above — 3:4 and 4:5 are both there, alongside 1:1 for squares.
From crop to exact pixels, honestly
A note on what this tool does and does not do. There is no field where you type 1080×1440 and receive that file in one step. Instead the exact size falls out of two operations done in order: lock the ratio first, scale second. Crop with the 3:4 chip and the proportions are fixed; resize that crop to a max width of 1080 and the height can only be 1440. The same sequence with the 4:5 chip produces 1080×1350, and with 1:1 produces 1080×1080. The order is what makes it exact — scale before you crop and you are back to eyeballing. Everything happens in your browser; the photos never leave your device.
Why 1080 wide, and what Instagram does to your file
Instagram serves feed images at up to 1080 pixels wide, and it re-encodes everything on upload. Both facts push the same direction: deliver a file that is already 1080 wide and moderately compressed, so the platform's encoder has as little work to do as possible. Upload a 4000-pixel original and you hand the re-encoder a scaling job plus a compression job, and its choices are not yours to review. Upload an over-crushed 200 KB file and the double compression stacks visibly — banding in skies, mush in fine texture. The middle path is a 1080-wide JPG at gentle-to-smart quality; the finer points of quality settings for the platform live on the compress-for-Instagram page.
Stories, Reels, and everything that is not a feed post
This page covers feed posts because that is what "Instagram post size" means when people search it, but the app's other surfaces have their own geometry: Stories and Reels are 9:16 full-screen (1080×1920), profile photos upload square and display round, and carousels follow the same feed rules as single images — with the wrinkle that every slide in a carousel shares the ratio of the first one, so crop the whole set to one shape before you start. Dimensions for those surfaces, and the other platforms' equivalents, are collected in the social media image sizes reference; for width-only resizing across Instagram's slots the resize-for-Instagram page has the presets.