Instagram Carousel Size: Dimensions, Ratios and Limits
Instagram carousel size is 1080x1350 at 4:5 or 1080x1440 at 3:4. Every ratio, the 20 slide limit, the API rules and what the 3:4 grid crops.
You export ten slides at 1080 by 1920, drop them into an Instagram carousel, and the headline on the first slide loses its top line. The fix starts with the frame. The best Instagram carousel size is 1080 by 1350 pixels at 4:5, or 1080 by 1440 at 3:4 if you want the tallest frame the feed shows. A carousel holds up to 20 photos and videos in the app, and every slide takes the shape of the first one.
That is the short answer. The longer one matters because Instagram has changed three things since 2024: the slide limit, the tallest allowed ratio and the shape of the profile grid. Its developer documentation has not caught up with all of them, so a carousel posted by hand and one posted by a tool follow different rules.
Instagram carousel size at a glance
| Frame | Size in pixels | Aspect ratio | What to know |
|---|---|---|---|
| Tall portrait | 1080 x 1440 | 3:4 | Tallest frame in the feed, matches the profile grid |
| Portrait | 1080 x 1350 | 4:5 | The safe default, accepted by the app and the API |
| Square | 1080 x 1080 | 1:1 | Cropped at the sides on the profile grid |
| Horizontal | 1080 x 566 | 1.91:1 | Takes the least space in the feed |
Instagram has supported 3:4 photos since May 2025, and according to The Verge's report, the format works for single photos and for carousels alike. Before that, 4:5 was the tallest portrait frame, so a 3:4 photo lost its ends to a crop. The other three frames are the ones Instagram has accepted for years.
Pick one row before you design anything. Every other decision in a carousel, from font size to where the text sits, follows from the frame.
Which Instagram carousel aspect ratio to pick
For most carousels, 4:5 is the right choice, and 3:4 is the right choice only when you post from the app yourself. The reason is the gap between the app and the API.
Meta's media reference for the Instagram API says an image must sit within a 4:5 to 1.91:1 range. A 3:4 image is taller than 4:5, so it falls outside that range on paper. If your carousels go out through a scheduler, an automation or an agent, 4:5 is the tallest frame you can count on. If you post by hand in the app, 3:4 gives you a little more height in the feed.
Square still has a place. A 1:1 slide is the frame that works on Instagram, on LinkedIn and as a square TikTok photo post, so one export covers all three. The cost is a smaller post in the Instagram feed and a crop on the profile grid, covered below.
Horizontal carousels are rare for a reason. A 1.91:1 slide uses less than half the height of a 4:5 one on a phone held upright, so text has to be small to fit, and small text is what people scroll past.
Instagram carousel dimensions in pixels
Width is where the pixel count comes from. 1080 pixels wide is the size templates and guides use, and the heights in the table above are simply 1080 multiplied out to each ratio.
Going wider gains you little. The API scales any image wider than 1440 pixels down to 1440, and anything narrower than 320 pixels up to 320, so a 4K export only makes the upload slower. A 1440 by 1800 file is the largest 4:5 image the API keeps at full size; 1080 by 1350 is the one every tool and template expects.
Export every slide at the same pixel size, not just the same ratio. A 1080 by 1350 slide next to a 1200 by 1500 one is the same shape, but scaled text will not line up from slide to slide, and that is visible the moment someone swipes.
The first slide sets the frame
Instagram does not mix shapes in one carousel. Meta's publishing documentation puts it plainly: carousel images are all cropped based on the first image, with 1:1 as the default. Guides that cover the app describe the same rule: the first image decides the ratio for the whole carousel.
That has two consequences. A square cover slide forces every slide after it into a square, so a 4:5 slide loses its top and bottom. A 4:5 cover does the reverse to a square slide in the middle of the set.
Design the carousel as a set, at one ratio, before you write a single headline. If one image in the set is a different shape, such as a screenshot or a product photo, place it inside a slide of the right size rather than uploading it on its own.
How many photos in an Instagram carousel
The app allows 20 photos and videos per carousel. Instagram doubled the limit on August 8, 2024, up from the 10 it had allowed since 2017, as TechCrunch reported at the time.
The API did not follow. Meta's publishing documentation still caps a carousel at 10 images, videos or a mix of the two, and the media reference repeats the same number. The Instagram carousel limit is therefore 20 when you post by hand and 10 when a tool posts for you. Plan any carousel that will be automated for ten slides or fewer, because the API does not accept an eleventh.
Twenty is a ceiling, not a target. One idea per slide, with a hook slide at the start and a closing slide at the end, keeps most carousels between six and ten slides. A longer set makes sense for a full tutorial or a recipe, where each step needs its own frame.
The 3:4 grid and what it crops
Your profile no longer shows square thumbnails. In January 2025, Instagram switched profile grids to rectangles, and Adam Mosseri explained the move in an Instagram Story, The Verge reported, saying most of what people upload is now vertical. The grid tile is 3:4.
A 3:4 post fits the tile exactly. Everything else gets cut at the sides when it shows on your profile, and the amount depends on the frame. Assuming a centered crop, the numbers work out like this for the first slide of a carousel:
| First slide | Shown on the grid | Cut from each side |
|---|---|---|
| 1080 x 1440 (3:4) | The full slide | Nothing |
| 1080 x 1350 (4:5) | The middle 1012 px of width | About 34 px |
| 1080 x 1080 (1:1) | The middle 810 px of width | 135 px |
The feed still shows the whole slide; only the profile thumbnail is cropped. For a 4:5 cover, keeping text about 50 pixels in from each side is enough. For a square cover, keep the headline inside the middle 800 pixels, or the grid will show half a word.
Moving a TikTok slideshow to an Instagram carousel
A TikTok slideshow is 1080 by 1920 at 9:16, as the TikTok slideshow size guide covers in detail. That is taller than any frame an Instagram carousel shows, so the same files cannot simply be uploaded again.
You have three ways to move a slideshow across:
- Crop to 3:4: cut 240 pixels from the top and 240 from the bottom of each 1080 by 1920 slide. This keeps the most of the original and suits posting by hand.
- Crop to 4:5: cut 285 pixels from the top and 285 from the bottom. This is the frame that also works through the API.
- Design square from the start: export 1080 by 1080 slides once and post them to both platforms, accepting a smaller post on each.
Cropping only works if the text was never near the top or bottom edge. Text placed a little above the middle of a TikTok slide, which is where the TikTok interface leaves room anyway, usually survives a 4:5 crop untouched. Headlines placed high on the slide do not.
Slide count and a frame that travels
The slide count needs a trim too. TikTok takes up to 35 photos, Instagram 20 in the app and 10 through the API, so a long TikTok slideshow has to be cut or split into two carousels.
Viral Slide Post renders slides in portrait 1080 by 1920 or square 1080 by 1080, and an agent connected through its REST API writes the text and can render up to 50 slides in one request. Viral Slide Post is in waitlist stage. Today its dashboard and REST API make slides and AI video clips and send them to TikTok; the MCP server, open source skills, Instagram publishing and scheduled posting are coming. Until then, the square frame is the one that moves between the two platforms without a crop.
File type, file size and captions
The rules below are the API's. They are also a sensible export standard for slides you post by hand, since a file that meets them works on both routes.
Meta's documentation sets the image format to JPEG, with extended formats such as MPO and JPS refused, and the file size to 8 MB at most. Images in other color spaces are converted to sRGB, so export in sRGB yourself and the colors you designed are the colors people see. A 1080 by 1350 JPEG at good quality comes out far below that 8 MB cap.
Use JPEG for every slide that goes out through a tool, even a flat text slide. The publishing documentation names JPEG as the only image format the API supports, so a PNG export has to be converted before a tool can post it.
The caption belongs to the carousel as a whole, not to each slide. The API allows up to 2,200 characters, 30 hashtags and 20 @ tags in it. Each image in a carousel can carry its own alt text of up to 1,000 characters, which is worth filling in for text slides, since a screen reader cannot read the words baked into the image.
Posting carousels through the API
If an automation or an AI agent posts your carousels, three more limits apply. Containers, the drafts the API builds before publishing, expire after 24 hours, and an account can create at most 400 of them in a rolling day. A carousel counts as one post against the publishing limit, whatever its slide count.
The publishing limit itself is where Meta's own pages disagree. The requirements section of the publishing documentation states 100 API-published posts in a moving 24 hour period, while the carousel section of the same page states 50. Plan for 50 a day per account until Meta settles it. Few accounts come close to either number, but an agent stuck in a retry loop can.
That retry loop is the real risk with automated carousels, and automating TikTok posting has the same failure mode. An agent that does not check whether its first attempt went through can publish the same carousel twice. Viral Slide Post's answer on TikTok is a draft that lands in the account's inbox for a person to finish, and its Instagram publishing is coming rather than shipped, so for Instagram today the guardrail is yours to build: check whether the post exists before the agent publishes again.
What to remember about Instagram carousel size
Use 1080 by 1350 at 4:5 as the default, and 1080 by 1440 at 3:4 only for carousels you post by hand from the app, since Meta's API still documents 4:5 as the tallest frame. Square at 1080 by 1080 is the frame that travels to other platforms, at the cost of a smaller feed post and a crop on the profile grid.
The first slide sets the shape of every slide after it, so design the set at one ratio and one pixel size. The app allows 20 slides and the API 10. The 3:4 profile grid cuts about 34 pixels from each side of a 4:5 cover and 135 from a square one, so keep headlines away from the edges. A 9:16 TikTok slideshow needs a crop of 240 or 285 pixels at the top and bottom before it fits, which only works if the text was placed near the middle to begin with.
