Meta Ad Sizes in 2026: The Spec Sheet for Facebook and Instagram

By Lukas Minnebeck, Co-founder of Superscale AI · Published May 17, 2026 · Updated May 17, 2026

Short answer for the operator opening five tabs at once: 1080×1350 (4:5) for feed, 1080×1920 (9:16) for Reels and Stories, 1080×1080 (1:1) for carousel and Marketplace, 1920×1080 (16:9) for in-stream. Images max 30 MB, video max 4 GB, MP4 or MOV with H.264. Everything else on this page is the why, the failure modes, and the placement-specific decisions that move CPM in 2026.

Most spec pages give you a table and call it done. We wrote this one because Meta's Andromeda delivery system (rolled out globally October 2025) now reads creative quality as a first-class ranking signal, and resolution and aspect-ratio choices that used to be cosmetic are now load-bearing. A Reel rendering at 480×854 instead of 1080×1920 isn't just ugly but it loses the auction.

Dimensions below come from Meta's own Ads Guide and Business Help Center, cross-checked against Meta's Reels image specs page and the Q1 2026 Tinuiti Digital Ads Benchmark Report. Verified the week of May 12, 2026.

The 2026 Meta ad sizes cheat sheet

This is the table to bookmark. Specs are Meta's published recommendations, not the absolute floor. The floor (where Andromeda starts penalizing you) sits roughly half the recommended on the short edge.

Text limits, on the same page: primary text 125 characters before "see more," headline 40 characters, description 30 characters. Organic-style captions allow 2,200 characters but only the first three lines render before truncation.

Universal video requirements: MP4 or MOV, H.264 video codec, AAC audio at 128 kbps or higher, 30 fps. Meta's documented max is 4 GB but anything over 1 GB hurts upload reliability. If you're shipping 50+ ads a week, that adds up.

Why placement-specific specs matter more in 2026

Three changes hit at once. None of them showed up on most operators' radar until Q1 numbers landed.

First, Andromeda. Meta's personalized-ads retrieval engine, launched on the NVIDIA Grace Hopper Superchip with model complexity 10,000× higher than the system it replaced, now treats creative as the primary targeting signal. A product shipped in three ratios (1:1, 4:5, 9:16) reads to Andromeda as three distinct entities and gets three retrieval shots. The same product shipped only as 1:1 and letterboxed into Reels reads as one weak creative across two placements. The auction punishes you twice.

Second, the Instagram placement shift. Per Tinuiti's Q1 2026 Digital Ads Benchmark Report, Reels rose from 19% of Instagram impressions in Q1 2025 to 33% in Q1 2026. Feed dropped to 26%, behind both Reels and Stories. Instagram CPMs declined 3% year-over-year for the first time since 2023, driven almost entirely by Reels share growth. If your library is 80% 1:1 square static, you're under-served on the placement that's growing and over-served on the one that's shrinking.

Third, the GEM update, the central delivery brain that connects to Andromeda across Facebook, Instagram, and WhatsApp. Andrew Foxwell, who covers Meta delivery weekly on Cobble Hill, frames it bluntly: Andromeda changed how Meta reads your ads, GEM changed how Meta reads your users, and the durable operator lever is creative diversification. He cites 30+ fresh concepts per month to unlock the algorithm's full delivery curve.

Compounding effect: specs are no longer a hygiene factor. They're a delivery lever. Every placement you ship at the wrong ratio is a placement Andromeda decides not to serve you on.

Facebook and Instagram feed: image and video specs

Both feeds now use the same dimensions, which is a 2026 simplification worth noting.

For images, 1080 × 1350 px at 4:5 is Meta's primary recommendation. 1080 × 1080 at 1:1 is supported but loses roughly a third of the mobile screen and consistently underperforms 4:5 in our accounts. JPG or PNG, 30 MB ceiling. Use JPG for photography, PNG only when you need transparency or sharp typography on flat color.

Video uses the same 1080 × 1350 at 4:5 (1:1 supported). MP4 or MOV, H.264, 4 GB ceiling, up to 241 minutes on Facebook and 60 minutes on Instagram. Sweet spot for paid feed is 15–30 seconds with a hook inside the first 1.5 seconds.

Meta's safe-zone recommendation: top 14% (about 250 px on a 1080×1350 asset) and bottom 20% (about 340 px) clear of text and logo. That bottom band is where the headline, CTA, and engagement chrome render. Agencies shipping into Meta the first time consistently miss this, and the headline obliterates the bottom third of the product shot.

When we audited a $25M-GMV apparel brand last fall, 60% of their top spenders had a logo lockup inside the bottom safe zone and were getting clipped on mobile. We pulled the logo, re-rendered the same files, and saw thumbstop ratio move from 27% to 38% on the duplicated ad sets within ten days. Same idea, same media buy, same audience.

Stories and Reels: the 9:16 vertical-first reality

Stories and Reels share the same dimensions, but they earn that placement differently. Both: 1080 × 1920 px, strict 9:16, MP4 or MOV, H.264, 4 GB max. Reels cap at 90 seconds for paid ads, Stories cap at 120 seconds of video per card. The performance sweet spot for both is 15–30 seconds.

Safe zones matter more here than anywhere else. Meta recommends leaving roughly 14% of the top, 35% of the bottom, and 6% on each side clear of key creative, text, or logos. That bottom 35% is the most aggressive safe zone Meta publishes on any placement because the profile icon, caption, hashtags, audio attribution, and CTA stack into that space. A founder talking-head Reel where the founder's mouth is in the bottom third reads as a meme on mute.

Resolution below 1080 px on the short edge is where Andromeda starts penalizing you. Meta's Reels image specs page lists 1080 × 1920 as the recommendation, with a 600 px short-edge floor for image and 720 px for video. We don't recommend running anything within 30% of those floors. The brand we mentioned at the top of this article was rendering at 540 × 960 because their video editor was exporting in "Reel preview" mode. The asset passed Meta's upload check, but the auction read it as low-quality creative and de-prioritized delivery. The CPM jump wasn't a penalty announced anywhere. It was the quality model doing its job.

On native pacing: Meta's delivery favors native vertical over re-edited horizontal shrunk into 9:16. A 16:9 webinar clip with a 9:16 frame around it reads as re-purposed and gets down-weighted. Shoot 9:16 native, or get good at vertical re-edits with real text overlay and pacing.

In-stream video and Marketplace

These two placements get ignored in most spec roundups. They shouldn't.

In-stream video runs before, during, or after other video content on Facebook and partner sites. Spec is 1920 × 1080 at 16:9 (1:1 fallback for mobile-feed roll-ups). Duration runs 5 seconds to 10 minutes, sweet spot 5–15 seconds, with the first 5 seconds non-skippable on most placements. That makes the opening frame the entire ad. Branding in the first 3 seconds isn't a best practice, it's the only way the placement works.

Marketplace uses 1:1 (1080 × 1080) for image and video. Users on Marketplace are in shopping intent, scanning a grid. Ads that look like organic listings (clean product shot, clear pricing context, minimal overlay) blend in and convert. Polished campaign creative reads as an ad and gets scrolled. The 1:1 format is non-negotiable; 4:5 or 9:16 assets get cropped square, rarely flatteringly.

Both placements deliver lower CPM than feed with thinner targeting depth. Useful for retargeting and catalog-style ads, less so for prospecting net-new audiences.

Carousel, Collection, and dynamic product ads

Carousel runs 2–10 cards, each at 1080 × 1080 at 1:1 (4:5 supported, but every card must share the same ratio or Meta defaults to the first card and crops the rest). 30 MB per image, 4 GB per video, images and videos can mix as long as the ratio holds. Primary text 125 characters, headline 40 characters per card.

Collection uses a hero asset (1080 × 1080 or 1080 × 1350) plus a product grid pulled from your catalog. Same per-asset ceilings. This is the format where hero spec drift hurts most, because the hero takes the full above-the-fold real estate on mobile and a low-res hero kills click-through to Instant Experience before the user sees the grid.

Advantage+ catalog ads (formerly dynamic product ads) inherit specs from the source catalog. The trap is the catalog image. Meta scales it aggressively, and catalog assets under 1080 px on the short edge look blurry across every placement. We've seen brands ship pristine 4096×4096 photography to their Shopify store and then push 600×600 versions through their Meta product feed because the feed was generated from a thumbnail field. Audit the image_url in your catalog, not what's on the storefront.

In early 2026 Meta opened limited testing of carousel and Advantage+ catalog ads on Threads with a 16:9 video shopping format. If you're in the test, the 16:9 spec is real and lifestyle horizontal product video performs noticeably better there than vertical re-cuts.

The 3 most common spec mistakes that quietly tank performance

Specs don't kill campaigns by failing the upload check. They kill campaigns by passing the upload check and then losing the auction. Here are the three failure modes we see most often in onboarding audits.

The first is the most painful because it's invisible. Meta pushes no alert. Ads Manager doesn't flag it. CPM moves first, diagnosis comes second, and most brands don't catch the half-resolution rendering until they pull a third-party tool to inspect the served bytes.

Aspect-ratio decision tree: when 1:1 vs 4:5 vs 9:16

Honest answer is "all three." If budget forces a single-format build:

• Reels and Stories are 9:16. No exceptions. 1:1 letterboxed into Reels is a placement you're not actually competing on.
• Feed defaults to 4:5. 1080 × 1350 grabs roughly a third more vertical screen on mobile than 1080 × 1080 and consistently lifts CTR in our accounts. Only reason to ship 1:1 in feed is consistency with carousel cards.
• Carousel and Marketplace are 1:1. Carousel mandates ratio consistency across cards. Marketplace's grid is square-native.
• In-stream is 16:9, the one Meta placement where horizontal still wins, because in-stream often serves on desktop and on connected-TV partners.

Portable rule: build every concept in three ratios from the start (1:1, 4:5, 9:16). Marginal cost of three rasters at production is a fraction of the delivery cost of forcing one ratio into the wrong slot.

How autonomous AI marketing agents handle multi-format resizing

We built Superscale AI as an autonomous performance marketing agent, not a creative tool you log into. Multi-format resizing is one of the cleaner illustrations of why agentic ownership of the creative loop matters in 2026.

The mechanical part: every creative the agent ships comes out in the correct aspect ratio for its target placement, automatically. There is no manual resize step. One brand brief produces parallel outputs across 1:1, 4:5, 9:16, and 16:9 in a single pass, with talent and product re-centered and safe zones respected per placement. The operator never picks the ratio. The agent picks the right one for each placement and ships all of them in parallel, so Andromeda reads them as distinct entities and runs a separate retrieval shot for each.

The closed-loop part is where it gets useful. The agent watches the served file in Meta Ads Library for each variant, confirms byte-level resolution matches what was shipped (catching the catalog-thumbnail problem and the half-resolution Reels problem), and if a variant under-delivers on a specific placement, re-cuts and re-launches. None of that requires a human, because none of it is a strategic decision. It's a hygiene-and-format loop that runs on the same daily cadence as the buying loop covered in our autonomous media buying piece.

This matters most for DTC brands shipping 50+ ads a week per the Andromeda fatigue cadence. Manual resize-and-QA at that volume eats two producers' weeks every month. Agentic resize-and-QA frees those producers to ship more concepts, which is the only lever Andromeda actually rewards.

The honest concession: the agent doesn't replace a creative director's eye on what concept to ship. It just stops the production team losing a day a week on resize hygiene and stops the media buyer chasing CPM ghosts that turn out to be the wrong export setting in Premiere.

FAQ

What's the best Meta video ad size in 2026?

For a single-format build, 1080 × 1920 at 9:16 covers Reels (33% of Instagram impressions per Tinuiti Q1 2026) and Stories without compromise, and Meta will auto-fit it to feed. For a production build, ship 4:5 (1080 × 1350) as the feed master and 9:16 (1080 × 1920) for Reels and Stories.

Why do my Meta ads get rejected for size?

Two reasons usually. Wrong file format (Meta wants JPG or PNG for images, MP4 or MOV for video; HEIC, MKV, AVI all fail). Or the file is over the ceiling (30 MB images, 4 GB video). Aspect-ratio mismatches don't trigger rejection. They trigger silent cropping, which is the worse outcome.

1080p vs 4K, does extra resolution help?

Meta caps its served file at 1080 px on the short edge for most placements. Shoot at 4K for the master (more re-frame flexibility, cleaner stabilization) but export at 1080 × 1920, 1080 × 1350, or 1080 × 1080. Uploading 4K is fine, Meta just transcodes down. No auction benefit, longer upload.

How do I fix a blurry Meta ad that passed the upload check?

Pull the asset from Meta Ads Library, save the served file, check its resolution. If it's under 1080 on the short edge, your source is below spec. Re-export at 1.5× the placement target (1620 × 2880 for Reels gives Meta transcode headroom), re-upload as a new ad rather than swapping in place, and let the new ad ramp.

Reels vs Stories: are the specs actually different?

Specs are identical: 1080 × 1920, 9:16, MP4 or MOV. The placements behave differently. Reels reward sustained watch time and audio-on engagement. Stories reward fast hook and short duration. Pacing that wins on Reels (15–30 seconds with a turn at second 7) often loses on Stories, where 6–10 seconds and an immediate hook win.

What's the carousel maximum number of images?

10 cards per carousel, 2 minimum. All cards must use the same aspect ratio. Images and videos can mix within one carousel as long as the ratio is consistent.

Does Meta actually penalize the wrong aspect ratio, or just crop it?

Both. Meta will crop a 1:1 asset into a 9:16 slot and serve it, but the served creative drives lower watch-through, and Andromeda reads weaker performance as a creative-quality signal. Visible failure is the crop. Expensive failure is the auction penalty.

Spec changes beyond Andromeda I should know about?

Three. Meta deprecated standalone desktop right-column-only ad sets in Q1 2026. Carousel and Advantage+ catalog ads entered limited Threads testing in early 2026 with a new 16:9 video shopping format. And per Tinuiti Q1 2026, Reels overtook Feed in Instagram placement share, so a library still weighted toward 1:1 is structurally under-delivered.

Methodology

Specs verified the week of May 12, 2026 against Meta's Ads Guide, Business Help Center image specs, Reels image specs, and Reels video specs. Placement-share and CPM data come from Tinuiti's Q1 2026 Digital Ads Benchmark Report. Andromeda and GEM commentary draws on Meta Engineering's published notes, Andrew Foxwell's Cobble Hill interview, and his Foxwell Digital writeup. Operator anecdotes are composites from Superscale onboardings between November 2025 and April 2026, dollar amounts rounded.