# The Exact Dimensions and Grid Math for Seamless Instagram Carousels > Slide sizes, master-canvas width, seam alignment, safe margins, and export settings for pixel-perfect panorama carousels. The reference, with the math. If you make seamless carousels, you eventually want the numbers, not the vibes. This is the reference: slide dimensions, how the master canvas scales, where the safe margins are, and what to export. If you just want to make one, start with [the panorama walkthrough](/blog/panorama-instagram-carousel/) instead. This page is for when you care about pixels. > **TL;DR** — Use 4:5 portrait slides, 1080 × 1350 px, up to 20 of them. The master canvas is slide-width × number-of-slides, and every slice must be exactly that width ÷ slide count. Export above 1080px (Jodu renders up to 3840px on the long edge) so Instagram's downscale stays sharp. ## Slide dimensions A carousel's aspect ratio is set by the **first slide**, and Instagram applies it to all of them. Pick one and commit. For feed posts your only sane choices are: | Shape | Aspect | Pixel size (per slide) | Notes | |---|---|---|---| | Portrait | 4:5 | 1080 × 1350 | Tallest the feed allows. Use this. | | Square | 1:1 | 1080 × 1080 | Safe, smaller footprint in-feed. | | Landscape | 1.91:1 | 1080 × 566 | Short. Avoid for panoramas, too little height. | Instagram displays everything at **1080px wide** and re-compresses on upload. You can't beat 1080 on their side, but you do want to *feed* it more than 1080 so the downscale stays sharp (more on that below). The slide count ceiling is **20**. That's your maximum panorama width. ## Master-canvas math A seamless carousel is one wide image sliced into equal columns. The master canvas is just the slide repeated *N* times across: ``` master width = slide width × number of slides master height = slide height (unchanged) ``` For 4:5 slides (1080 × 1350): | Slides | Master canvas | Aspect of the whole | |---|---|---| | 2 | 2160 × 1350 | 1.6 : 1 | | 3 | 3240 × 1350 | 2.4 : 1 | | 4 | 4320 × 1350 | 3.2 : 1 | | 5 | 5400 × 1350 | 4 : 1 | | 10 | 10800 × 1350 | 8 : 1 | Every slice has to be **exactly** `master width / N` wide. This is the bit people get wrong by hand. A rounding error of even one pixel per slice adds up into a visible step by the time you reach the far seams. If you're slicing manually, make your master width divide cleanly by your slide count. In [Jodu](https://apps.apple.com/app/jodu-app/id6759936736) you don't compute any of this. You design on one continuous canvas and it renders each slide as an equal column at export, so the seam math is exact by construction. ## Seams and safe margins Two different margins matter, and they're easy to mix up. - **Seam tolerance.** Artwork that crosses a seam needs to sit against a true vertical cut rather than a hand-judged one. With exact equal slices, the crossing is lossless. The only risk is in the slicing itself, which is the math above. - **Content safe margin.** Keep text, and anything you don't want landing on a fold, about 10% in from each slide edge. That's roughly **108px** on a 1080-wide slide. Either commit to an element crossing the seam on purpose, or keep it well clear. The dead zone is just the few pixels right on the cut. - **The grid-thumbnail crop.** Your profile grid crops **slide one to a center square** (1:1). Keep slide one's key subject and any logo or title within the centered 1080 × 1080 region, or it'll be clipped in the grid even though it's fine in the post. ## Export settings What you hand Instagram matters as much as what you designed. - **Oversample, then let Instagram downscale.** Export well above 1080px wide per slide. Jodu renders each slide at up to **3840px on the long edge**. For a 4:5 slide that works out to **3072 × 3840**. Then Instagram's downscale to 1080 × 1350 lands clean instead of mushy. - **Format.** Instagram re-compresses to JPG regardless, but exporting **PNG** for flat color, text, and sharp edges gives the recompressor a cleaner source. Photo-heavy slides are fine as high-quality JPG. - **Equal slices, in order.** Render per-slide (not "export the whole thing and crop later") so each file is an exact, independent column. Jodu exports each slide separately and shows a swipeable preview of all of them before you save. That's your last seam check. - **Upload order.** Select slides left-to-right when you post. Instagram keeps the order you tap them, and a single out-of-order tap scrambles the panorama. ## Quick-reference ``` Recommended slide: 1080 × 1350 (4:5 portrait) Max slides: 20 Master width: 1080 × N Slice width: master width ÷ N (must be exact) Content safe margin: ~108px from each slide edge Grid-crop region: center 1080 × 1080 of slide 1 Export target: up to 3840px long edge per slide (≈3072 × 3840 at 4:5) ``` ## FAQ ### What is the best size for an Instagram carousel? 4:5 portrait, 1080 × 1350 px. It's the tallest shape the feed allows, so it gives each slide the most screen space. Square (1080 × 1080) also works. ### How many slides can an Instagram carousel have? Up to 20 in a single post. ### What dimensions should a seamless / panorama carousel be? Each slide stays 1080 × 1350 (4:5). The full master image is slide-width × number-of-slides wide, for example 3240 × 1350 for 3 slides, sliced into equal 1080-wide columns. ### What resolution should I export carousel slides at? Higher than 1080px wide per slide, so Instagram's compression stays sharp. Jodu renders each slide at up to 3840px on the long edge (about 3072 × 3840 for a 4:5 slide). --- *Part of a 3-part series. The [panorama walkthrough](/blog/panorama-instagram-carousel/) covers the craft, and the [beginner's guide](/blog/seamless-instagram-carousel/) covers the basics. Jodu handles all of the slicing math for you.* --- Source: https://jodu.app/blog/instagram-carousel-dimensions/ A free iPhone collage app that handles the carousel slicing math for you. Design on one canvas; it exports perfectly aligned 4:5 slides at up to 3840px.