Every blurry, awkwardly-cropped carousel on Instagram is a sizing mistake that took two seconds to make and cost the post its polish. The rules are simple but unforgiving — Instagram silently crops or compresses anything that doesn't match its supported ratios. Here are the exact numbers, the safe zones, and the workflow that makes sizing a non-decision.
The one answer: 1080×1350
If you take one number from this page: make every carousel slide 1080×1350 pixels — 4:5 portrait.
Why this beats the alternatives:
- It's the tallest feed format. A 4:5 post fills ~25% more screen than a 1:1 square and ~78% more than 1.91:1 landscape. In a feed, screen area is attention.
- Every slide inherits slide 1's ratio anyway. Instagram locks the carousel to the first slide's aspect ratio, so "mixing" isn't an option — you're choosing one ratio for the whole set. Choose the biggest.
- It survives the grid crop gracefully. Your profile grid shows a center crop; a 4:5 design with centered content previews cleanly.
Full reference table:
| Format | Pixels | Ratio | Verdict |
|---|---|---|---|
| Portrait | 1080×1350 | 4:5 | Use this |
| Square | 1080×1080 | 1:1 | Fine, smaller presence |
| Landscape | 1080×566 | 1.91:1 | Avoid for carousels |
| Reels-size | 1080×1920 | 9:16 | Gets cropped to 4:5 in feed carousels — don't |
That last row is the most common self-inflicted wound: repurposing a 9:16 story/reel design into a carousel and losing the top and bottom of every slide.
Safe zones inside the slide
Correct canvas size isn't enough — Instagram's UI overlays eat into your design:
- Bottom ~180px: caption, like/comment row overlap here in some surfaces. No critical text.
- Top ~150px: your username and the ⋯ menu.
- Right edge: the slide counter ("2/8") sits top-right.
- Center-safe rule of thumb: keep headlines and CTAs inside the middle 80% both directions, and nothing important within 60px of any edge.
Design rules that ride on the sizing
- One idea per slide. The swipe is a pacing mechanism; cramming defeats it.
- Slide 1 is a headline, not a summary — its only job is stopping the scroll and earning the first swipe.
- Design the set as one system: same background, type scale, and accent colors on every slide. Consistency is what makes a carousel feel authored rather than assembled.
- End with a CTA slide — follow, save, or link. Saves weigh heavily in carousel distribution.
- Export without recompression: if your tool offers quality settings, maximum quality PNG or high-quality JPEG at exact dimensions. Instagram will compress once; don't make it twice.
Make sizing a solved problem
The reason sizing mistakes keep happening is that every new post re-opens the question. The fix is templates: define your carousel formats once — 1080×1350 canvas, safe zones respected, brand fonts and colors locked — and produce every post inside them. In FeedForce, the template editor bakes the dimensions and your brand kit into the format, so a new carousel is filling slots, not re-deciding geometry; and if you distribute beyond Instagram, the same design fans out with the right per-platform treatment (see posting everywhere at once).
Get the number right once, systematize it, and spend your attention on the part that actually ranks you in feeds: what the slides say.