An Instagram carousel has one aspect ratio, set by the first slide, and every other slide is cropped to match it. Export every slide at the same size, 1080×1350 (4:5) or 1080×1440 (3:4), as a JPEG between 500 KB and 1 MB, and the carousel posts exactly as you built it. You can include up to 20 slides. The only exception to the one-ratio rule is a Mixed option that newer app versions offer, which is useful but not something to rely on yet.
That is the short version. The rest of this guide is what happens when you break each of those rules, how seamless multi-panel carousels are built, and what to check before you tap Share.
One ratio per carousel, and the first slide decides it
When you select several photos in the composer, Instagram looks at the first one and applies its ratio to all of them. If you tap the crop icon at the bottom left of the preview and choose square, portrait or landscape, that choice applies to every slide too. Slides that are a different shape are cropped from the centre. You can drag each slide within the fixed frame to choose what stays, but you cannot give slide three a different shape from slide one.
The consequence: if slide one is a landscape photo, every portrait in the set is cut down to landscape and loses most of its height. If slide one is a screenshot at 9:16, the whole set is squeezed to 4:5. Order the slides deliberately, and better still, export them all at one size before you open Instagram so there is nothing to crop.
The Mixed option
During 2025 Instagram started showing a Mixed option in the crop menu when the selected photos have different shapes. It keeps each photo's own ratio and adds borders around the wider ones so the layout still works. Instagram never documented it; it was tested with a small group in the summer and reached most accounts by the autumn, and some people still report it appearing and disappearing between app versions.
Use it if you have it and the set genuinely mixes portraits and landscapes. Do not build a workflow on it. It still crops anything outside Instagram's allowed range, and the profile grid still takes its tile from the first slide, cropped to 3:4 like any other post. For anything that matters, one ratio for the whole set remains the reliable choice.
Which size to use
| Ratio | Pixels per slide | When |
|---|---|---|
| 4:5 portrait | 1080×1350 | The default. Most screen in the feed, nearly full in the grid |
| 3:4 tall | 1080×1440 | When the first slide must fill the profile grid exactly |
| 1:1 square | 1080×1080 | Product sets and older libraries; looks smaller in the feed |
| 1.91:1 landscape | 1080×566 | Almost never; every slide becomes a thin strip |
4:5 is the safe answer. It has always displayed uncropped in the feed and it loses only about 34 px on each side in the 3:4 grid. 3:4 is the better answer when the grid tile matters; Instagram has accepted it natively since May 2025 for single posts and carousels alike, and the 3:4 size page exports it directly. Whichever you choose, the width is 1080 px, the width Instagram keeps without scaling.
Video slides follow the same ratio as the photos. A 9:16 clip in a 4:5 carousel is cropped to 4:5, so frame the clip with that in mind or trim it to 4:5 in your editor first.
Up to 20 slides
The limit is 20 slides per carousel. Slide one is the cover: it is what the feed shows first and what the profile grid shows as the tile, cropped to 3:4 from the centre, so give it the same margins you would give a single post. The grid guide explains that crop in detail.
After posting you can remove a slide, but you cannot add, reorder or recrop one. Check the order before you share.
Seamless multi-panel carousels
A seamless carousel is one wide image cut into slides, so the picture continues as people swipe. Instagram shows slides edge to edge with no gap, which makes it possible, and the whole thing depends on the slices being exact.
- Decide the number of panels and the ratio. For 4:5 slides the canvas is 1350 px tall and 1080 px wide per panel: 2160×1350 for two, 3240×1350 for three, 4320×1350 for four. For 3:4 slides use 1440 px tall.
- Design on that canvas. Keep faces and text away from the seams, because a swipe that stops halfway shows the join.
- Cut the canvas into slices exactly 1080 px wide. Any rounding (a 1079 px slice, a 1 px gap) shows as a hairline between panels.
- Export every slice as a JPEG, sRGB, between 500 KB and 1 MB, and name them in order (01, 02, 03).
- In the composer select them in order and do not touch the crop. The ratio is already correct, so Instagram has nothing to cut.
The one thing to accept: the feed shows the cover panel alone until someone swipes, and the grid tile is the cover panel cropped to 3:4. Design the first panel to work on its own.
File size per slide
Every slide is re-encoded separately, so each one follows the same rule as a single post: 1080 px wide, JPEG, between 500 KB and 1 MB. Under about 300 KB a photo slide has already lost detail and comes out blocky after Instagram's pass; over about 2 MB it is compressed harder. Twenty slides in the band add up to 10 to 20 MB of upload, which is fine on Wi-Fi and slow on a weak signal, so post carousels on Wi-Fi with Upload at highest quality on and data saver off.
One nuance for design slides. A flat graphic with text and solid colour is naturally small; at a high quality setting it may be 200 KB with nothing missing. The rule is about not lowering quality to hit a small number, not about padding files up. Export design slides at a high quality setting and let the size be what it is. If the tool cannot reach 500 KB for a flat design, it simply exports at the highest quality, which is the right result.
Rule: same ratio, same pixels, same file-size band for every slide. Instagram then treats the carousel as twenty identical single posts, which is exactly what you want.
Common mistakes
- Mixing ratios without Mixed. The set is cropped to slide one and someone's head is missing on slide four. Export everything at one size.
- A landscape first slide. The whole carousel becomes 1080×566 strips. Put a portrait first, or crop the landscape to 4:5 with margins.
- Text at the edges. Composer crops and the 3:4 grid both take the edges. Keep text inside the middle of the frame, and on 4:5 slides at least 40 px in from the sides.
- Slides at different pixel sizes. One slide exported at 3000 px and another at 1080 px are resized differently by Instagram and end up with different sharpness. Export all of them at 1080 px, sharpened after the resize.
- Screenshots as slides. Wrong size, PNG, small text. Resize and sharpen them, or rebuild the content as a design slide.
- PNG exports. Design apps often export PNG by default. Instagram converts it to JPEG anyway; a PNG only makes the upload bigger and slower. Choose JPG at high quality.
- Uploading on data saver. With Use less mobile data on, the app can reduce every slide before it leaves the phone. The HD upload settings guide shows where the switch is.
Export all the slides at once
The tool below takes up to 50 photos in one go. Choose Post 4:5 or Post 3:4 once, drop the whole set, drag any slide whose crop needs moving, and download them all as a ZIP or share them one by one. Every slide comes out at the same pixel size, sharpened after the resize, with a JPEG quality chosen to land between 500 KB and 1 MB. Nothing is uploaded; it runs in your browser and works offline.
What this cannot do
No export fixes a carousel after it is posted; the ratio and the crops are locked when you share. And no tool makes Instagram show mixed shapes on an account that does not have the Mixed option yet. If a set must combine portraits and landscapes today, put each on a 1080×1350 canvas with a plain background, so the borders are yours and every slide is still 4:5.
Checklist
- One ratio for the whole set, decided by slide one: 1080×1350 or 1080×1440
- Up to 20 slides, in order, with the cover designed to work alone
- Seamless sets: exact 1080 px slices from a single canvas
- Every slide a JPEG, sRGB, 500 KB to 1 MB, sharpened after the resize
- Text and faces inside the centre of each slide
- Wi-Fi, Upload at highest quality on, data saver off
Get the first slide right and the other nineteen follow.