Meta Feed Ad Specs: Ratios, Sizes, and Placement Rules

Meta feed ads (Facebook and Instagram feed) work best in vertical-leaning ratios — 4:5 is the workhorse for feed because it fills more of the screen than square 1:1 or landscape, while full 9:16 belongs to Reels and Stories placements. Render at 1080 pixels wide or more, keep text and product inside the frame's core so nothing important sits at the edges, and check Meta's ads manager for the current file-size, length, and text requirements, since those details get revised. The stable principle: match the ratio to the placement instead of forcing one asset everywhere.

Which aspect ratio should I use for feed?

For feed specifically, 4:5 vertical is usually the strongest default — it occupies more vertical screen space than 1:1 and far more than 16:9, without spilling into the full-screen territory reserved for Reels and Stories. Square 1:1 remains a safe fallback that renders acceptably across many placements. Landscape 16:9 gives away screen real estate on mobile, where most feed impressions happen.

Should one ad run across all Meta placements?

Meta will happily distribute one asset everywhere via automatic placements, but ratios that flex look better than ratios that stretch. A practical setup: a 4:5 cut for feed and a 9:16 cut for Reels and Stories, built from the same creative. Meta's placement customization lets you assign the right ratio to the right slot rather than letting the system crop for you — automatic crops routinely chop off captions and product shots.

What are the safe areas in feed?

Feed doesn't overlay as much UI on the creative as Reels does, but the primary text sits above the ad and the headline and CTA sit below it, so the creative itself must carry the message without depending on those fields being read. Inside the frame, keep burned-in text away from the extreme edges, where cross-placement cropping can trim it.

Does the hook still matter in feed?

Yes — feed is a scroll, and video ads autoplay muted, so the first frames must stop the thumb visually. Design for sound-off: on-screen text and a strong opening image do the work, with sound as a bonus. Your hook rate shows whether openings are landing, and a hook generator gives you more openings to test than you'd write by hand.

What determines results once specs are met?

Meta's auction rewards creative variety: outcomes hinge on your margin, audience, and how many distinct angles you test — not on hitting the pixel dimensions, which everyone hits. Predicting ROAS per ad in advance isn't realistic; producing enough variations to find winners is. Polaris makes that production step conversational — connect it to Claude via MCP, attach a product photo, and generate batches of UGC-style ads inside Claude, sized for the placements you're running. Start with AI UGC ads (first batch of 12 free), then run the numbers through a ROAS calculator to see which variants clear your margin.