Instagram Post Size Guide 2026: Post, Story, and Reels Dimensions

Before we go format by format, here is the fastest way to check your Instagram post size across every placement:

Before choosing a pixel size, it helps to understand why dimensions matter so much here. Instagram compresses every upload to save server space, and any image that doesn't match a supported aspect ratio gets stretched, squeezed, or cropped without warning. That's why so many creators search for the exact image size for an Instagram post instead of uploading photos straight off a phone or camera. Matching the recommended pixel dimensions from the start preserves sharpness and stops the compression algorithm from degrading your resolution any further.

Feed posts support three main aspect ratios, and the one you pick directly affects how much of your image gets cropped in the grid, how large it appears on someone's screen, and how much scroll-stopping space it occupies.

In 2026, Instagram began testing a shift from the classic 4:5 crop preview toward a 3:4 grid ratio on some profile pages. This changes how thumbnails are cropped in the grid view, not the upload pixel size itself. Your 1080 × 1350 files still upload correctly, but the top and bottom edges may be trimmed a little more in the grid thumbnail than before. That distinction has caused real confusion among creators who assumed the official upload size had changed entirely.

In a carousel, every slide should use the same dimension, otherwise you get mismatched cropping and jarring transitions as people swipe. The ideal size is 1080 × 1350 pixels (4:5), matching the standard portrait post ratio, since it gives each slide maximum visibility.

Mixing square and vertical slides in the same carousel is one of the most common format mistakes creators make, and it usually ends with Instagram auto-cropping later slides to match the frame of the first one. Design the full carousel on a single canvas size from the start and the problem never appears.

The standard Instagram Story size is 1080 × 1920 pixels, a full-screen 9:16 vertical ratio that fills the entire mobile display. Keep essential text, stickers, and calls-to-action clear of the top 250px and the bottom 250px, where Instagram's own interface (the profile bar and the reply field) sits over your content.

Reels use the same 1080 × 1920 pixel, 9:16 format as Stories, so your video fills the entire screen without black bars or letterboxing. The Reels cover thumbnail should also be cropped in a portrait-safe zone, either 9:16 or 1:1, so it reads correctly both in the main feed and in the profile grid, where it appears as a small static preview.

Correct dimensions only get the Reel played. Holding the viewer past the first few seconds is a separate problem: transitional hooks make videos harder to skip at the exact points where people usually drop off.

Your profile picture displays at 320 × 320 pixels, but upload a square image of at least 1080 × 1080 so it stays sharp on high-resolution screens. Since the photo is cropped into a circle, keep your subject or logo centred and leave padding around the edges so nothing important gets clipped by the circular mask.

Ad creatives follow the same core aspect ratio logic as organic posts, but with stricter file and format requirements for approval, since a single ad runs across multiple placements at once.

Almost every sizing problem on Instagram traces back to one of four habits: