Updated October 2026
Instagram supports several different aspect ratios depending on content type, and it's easy to mix them up when planning a post. This page is a quick reference covering every common format, with carousels (this site's focus) covered in the most detail.
| Format | Aspect ratio | Pixel dimensions |
|---|---|---|
| Square | 1:1 | 1080 × 1080 px |
| Portrait | 4:5 | 1080 × 1350 px |
| Landscape | 1.91:1 | 1080 × 608 px |
Portrait (4:5) is the tallest ratio Instagram allows in-feed, which is why it's the default in this tool's carousel splitter — it uses the most available vertical screen space per slide while scrolling.
| Format | Aspect ratio | Pixel dimensions |
|---|---|---|
| Stories | 9:16 | 1080 × 1920 px |
| Reels | 9:16 | 1080 × 1920 px |
Stories and Reels use a much taller, full-screen vertical ratio designed for full-device viewing rather than scrolling through a feed grid — a different design problem from a carousel, which needs to look complete both in the scrolling feed and when opened.
A 9:16 ratio is extremely tall relative to its width — fine for a single full-screen view, but it would make each individual carousel slide look like a narrow sliver in the feed grid view (where Instagram shows a cropped square preview of each post) and would leave very little usable width per slide once split across multiple slides. The 4:5 portrait ratio is specifically Instagram's compromise for in-feed content that still needs to read well both in the grid and when opened.
Regardless of which aspect ratio you post at, Instagram's profile grid shows a square-cropped preview of each post's first slide. If you post a Portrait (4:5) carousel, be aware that the grid thumbnail will show a center-cropped square version of slide 1 — worth checking that your first slide's key content stays within the central square area if the grid-preview appearance matters to you.