The Facebook ad sizes that actually hold up in 2026.

Here's the inside scoop: most marketers copy their Facebook ad sizes from whatever guide ranks first, and right now, that's a problem. I spent this week cross-checking a dozen "complete 2026 guide" posts against each other and against Meta's own Ads Guide. The core Feed, Stories, and Reels dimensions turned out to be solid and consistent everywhere. But a handful of newer, more specific claims, Reels length caps, right column ratios, Messenger sizing, contradict each other from post to post, sometimes within the same week.

So this guide does something different. It gives you the Facebook ad sizes that are actually verified for 2026, flags the ones that aren't, and tells you exactly where to check before you build your next campaign.

Why Andromeda raised the stakes

Meta's ad delivery system got a full rebuild starting in Dec. 2024, when Meta's engineering team introduced Andromeda, a personalized ads retrieval engine built to keep pace with the exploding number of ad creatives entering the system. The practical result: Meta increasingly reads your creative itself, not just your manual targeting settings, to decide who sees your ad. We broke down how Andromeda changed creative testing in more detail if you want the full mechanics.

A Reel at the wrong resolution or a Story with its CTA buried under Meta's UI chrome isn't just a design miss anymore. It's a weaker signal into a system actively reading that creative to decide distribution.

Feed ads: the specs everyone agrees on

Feed is the placement where all sources line up, so treat it as safe to build from without double-checking.

ElementImage adsVideo adsResolution1,080 x 1,080 px (1:1) or 1,080 x 1,350 px (4:5)Same ratios as the imageFile formatJPG or PNGMP4, MOV or GIFMax file size30 MB4 GBMax lengthNot applicableRoughly 240 minutes, though most sources agree anything past 15 to 60 seconds hurts completion rate

A few practical notes on top of the table. Upload higher than the 1,080 px floor when you can, since Meta compresses everything on the way in and extra resolution protects against artifacts. A common practitioner benchmark is 1,440 x 1,440.

On text overlays: Meta stopped enforcing the old rule that flagged images with more than 20% text coverage, but it still recommends staying under that line since heavier text tends to reduce delivery. That guidance appears directly on Meta's own creative best practices page for ad text, so it's worth bookmarking rather than a third-party recap.

Primary text performs best under 125 characters before it gets truncated behind "See more." Headlines top out around 27 to 40 characters, depending on placement, so keep your strongest phrase in the first few words regardless.

Stories and Reels: get the safe zone right

Both placements use 1,080 x 1,920 px (9:16), full-screen vertical, a minimum width of around 500 to 600 px. That part is uncontested.

Where a lot of guides get sloppy is the safe zone, and this is worth fixing because it is the single most common reason a Stories or Reels ad looks unfinished. The margins are not symmetrical. Keep roughly the top 14%, the bottom 20% to 35%, and 6% on each side clear of logos, captions, or your call-to-action button. The bottom band is wider than the top because that is where Meta's caption, CTA and engagement UI actually render, and treating it the same as the top margin is how CTAs end up hidden behind the interface.

Heads up: the exact Reels maximum video length is one of the specs still in dispute across current guides; some report 60 seconds, others 90, and Meta's own published guidance on this specific point is inconsistent enough that no single number checks out across sources right now. Rather than repeat a number that might already be wrong by the time you read this, check the length limit shown directly in Ads Manager when you upload.

Carousel ads: cards, ratios and limits

Carousel specs are consistent across sources. Use 2 to 10 cards, each at 1,080 x 1,080 px (1:1). Images can be up to 30 MB per card and videos up to 4 GB per card, and every card in a single carousel should share the same aspect ratio. Mixed ratios within a single carousel are cropped unpredictably rather than rejected outright, which is a quieter failure than most advertisers expect.

Primary text applies to the whole carousel and works best at around 80 to 125 characters. Each card gets its own headline (aim for 30 to 45 characters) and an optional short description that many advertisers skip entirely since it is easy to truncate.

Right column and Messenger: still in flux

This is the section where I would slow down before you build anything. A few widely repeated 2026 claims about right-column and Messenger ads do not hold up under cross-checking.

The right column has long been a small, desktop-only placement, and sources are currently split on whether it is now square only (1:1) or still supports the older 1.91:1 landscape ratio. Both claims show up in guides dated within the last two months. Similarly, Messenger inbox ad dimensions are reported inconsistently; most sources cite 1:1 at 1,080 x 1,080 px, but a few list the 1.91:1 link preview size instead, which is a different spec entirely and shouldn't be assumed to be interchangeable.

Rather than pick a side here, the honest move is to verify directly against Meta's Business Help Centre image specifications and aspect ratio guidance before you lock creative for either placement. It takes five minutes, and it is the only way to be certain right now.

What the Reels data actually shows

Let the data tell the story here, because it is more useful than another spec argument. On its Q1 2026 earnings call, Meta reported that ranking improvements drove a 10% lift in Reels time spent on Instagram, while total video time on Facebook grew more than 8% globally, its largest quarterly gain in four years. Same-day posts now make up more than 30% of recommended Reels across both apps, more than double the share from a year earlier. That is Meta describing its own delivery priorities, not a third-party estimate.

The strategic read: if your creative library is still weighted mostly toward 1:1 static Feed assets, you are underbuilt for the placement that is actually growing and overbuilt for the one that is shrinking. Building a proper 9:16 asset for every concept is no longer a nice-to-have; it is where a growing share of your impressions is already landing. Our 9:16 first creative checklist walks through how to restructure a shoot around that priority.

The bottom line

The core Facebook ad sizes for 2026 are more stable than the noise around them suggests: 1,080 x 1,080 or 1,080 x 1,350 for Feed, 1,080 x 1,920 for Stories and Reels, 2 to 10 cards at 1,080 x 1,080 for carousel. The real risk lies in the newer, more specific claims about Reels length, right-column ratios, and Messenger sizing, and the fix is not to memorize a new number; it is to verify directly with Meta before you build.

A few habits keep you out of the contradiction trap this guide just walked through:

• Bookmark Meta's own Ads Guide and check it directly for anything you are not 100% sure of, rather than trusting a third-party recap.
• Treat any spec labelled "as of 2026" with a healthy dose of skepticism until you have seen it in two independent sources, ideally including Meta itself.
• Build your creatives at 1,080 x 1,080 and 1,080 x 1,920 as your two default masters. That combination covers the large majority of placements and gives you a safe starting point while contested specs get sorted out.
• Preview every asset in Meta's Creative Hub before launch; it catches cropping and safe zone issues before they cost you spend.

Confirm your two default asset sizes are locked, check any placement-specific information directly against Meta before you spend against it, and you are already ahead of most of what is currently ranking on this topic. Ready to put this into practice? Grab our Meta ad spec cheat sheet and skip the guesswork on your next build.