Every platform accepts a slightly different carousel, and the differences are big enough that one exported image set won't serve all three well. Here are the numbers, and then the part that actually matters — which is what to do about them.
The short version
- Instagram — 1080×1350 (4:5 portrait), up to 10 slides.
- TikTok photo mode — 1080×1920 (9:16 vertical), between 2 and 35 images.
- Facebook — 1080×1350 works well; a multi-photo Page post has no practical slide limit.
Instagram carousels
The maximum is 10 slides, and the best size is 1080×1350 — the 4:5 portrait ratio. Square (1080×1080) is still supported and still fine, but 4:5 occupies more vertical space in the feed, which gives a cover slide a longer moment in front of someone who is scrolling quickly.
Every slide in a carousel is cropped to the ratio of the first one, so a mixed set will be trimmed to match the cover. That's the single most common way a carousel ends up with headlines cut off — not a wrong size, but an inconsistent one.
Publishing through the API requires a Business or Creator account. That's Instagram's rule rather than any tool's, and switching a personal account over takes about a minute in the app.
TikTok photo mode
TikTok's photo posts — also called photo mode, slideshows or carousels depending on who you ask — are vertical, so 1080×1920 at 9:16. The platform accepts between 2 and 35 images, which is far more than you should use: a set that takes thirty swipes to finish tends to lose people around slide six.
Because the ratio is so much taller than Instagram's, this is where reusing one export goes wrong most visibly. A 4:5 image placed into a 9:16 frame either gets letterboxed or gets cropped, and cropping a carousel designed for Instagram usually takes the top off the headline.
An organic Facebook carousel is a multi-photo Page post: several images attached to one post that people swipe through. It's the most forgiving of the three — 1080×1350 works well, and there's no slide limit you're likely to hit.
Worth separating from the paid carousel ad, which is a different product with its own creative specs and per-card links, built in Ads Manager. If you're searching for "Facebook carousel size" you might mean either; the difference is covered here.
How many slides should you actually use?
Fewer than the maximum. The limits are technical ceilings, not targets. Six to eight tends to be the sweet spot on all three platforms: enough to develop an idea, short enough that someone finishes it, and short enough that you can make one without it becoming an afternoon.
The structure matters more than the count. A cover that earns the swipe, one idea per slide after that, and a final slide that asks for something specific — that shape works at six slides and at ten, and no amount of extra slides rescues a set that doesn't have it.
Don't crop one set three ways
The temptation with three sets of dimensions is to design once at the largest size and crop down. It saves an hour and costs you the headline on at least one platform, because the safe area for text at 4:5 is not the safe area at 9:16.
If you want to see that on your own slide rather than take my word for it, the carousel safe zone checker draws the profile-grid crop and TikTok's interface over an image you drop into it. Nothing is uploaded — it runs in the browser.
Rendering each platform separately from the same content is the version that works: same copy, same design system, laid out for the frame it's going into. That's what SlideBuddy does — a carousel approved once is composed at 1080×1350 for Instagram and Facebook and again at 1080×1920 for TikTok, rather than one image squeezed into three shapes.
Quick reference
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