Banner Ad Sizes: The Standard IAB and Google Formats

The banner ad sizes that carry most display inventory are 300 x 250, 728 x 90, 160 x 600, 300 x 600, and 320 x 50 pixels. Google supports around twenty fixed sizes for uploaded display ads and caps each image file at 150KB; the IAB publishes a shorter recommended set with its own file weight limits. Build those five first, add 970 x 250 and 336 x 280 if you have budget for them, and you cover the placements that actually serve. Below is the full spec from both sources, the naming for each size, the file weight rules, and how the responsive formats change the math.

Banner ad sizes: the standard spec

These are the sizes worth building first, with the names each standards body uses for them. Dimensions come from Google's uploaded display ads specifications and the IAB Tech Lab New Ad Portfolio fixed size ad specification.

Two things about that table are worth stating plainly. First, the two standards do not name sizes identically: 300 x 250 is an "inline rectangle" in the Google Ads interface and a "medium rectangle" almost everywhere else, and both refer to the same 6:5 box. Second, not every size a network accepts is a size the IAB recommends. Google's list is longer because it is an accepted-uploads list, while the IAB list is a recommended portfolio built around the units that produced most revenue across screen sizes.

Google display ad sizes: the full accepted list

If you are uploading your own image creative rather than letting Google assemble it, these are the google display ad sizes the Display Network accepts, grouped the way Google groups them:

File requirements for those uploads, straight from the same Google page: GIF, JPG, or PNG, with a maximum of 150KB per image ad. HTML5 creative is uploaded as a ZIP up to 600KB, and AMPHTML ads use the same 600KB ZIP ceiling. Google also lists a few region-specific sizes, such as the 750 x 100 Polish billboard, which most advertisers can ignore.

Twenty sizes is more than any sane team designs by hand. In practice most accounts ship the five or six units above and let responsive formats fill the rest, which is the next section.

IAB standard ad units and file weight limits

The IAB Tech Lab's fixed size specification is shorter and comes with something Google's list does not have: per-unit file weight budgets, split into initial load (what renders the first frame) and subload (what may download after the page load event fires).

The spec also defines a flexible sizing grid for formats outside that list, banding k-weight by total pixel count. A 300 x 600 half-page and a 970 x 250 billboard both land in the 700 to 900 thousand pixel band, which allows 250 kB initial and 500 kB subload, with 250 kB as the ceiling for a static image. Note the IAB sizes fixed units at double density, so 728 x 90 is treated as 728 x 90 x 4 = 262,080 pixels for grid purposes.

Two more rules from that document that quietly break creative: no more than ten file requests during initial load, and file weights are measured after gzip. On connections of 1.5 Mbps or slower, the IAB recommends dropping weights another 30 percent.

Responsive display ads: three assets instead of twenty

Fixed sizes are no longer the default way most Google Display campaigns run. Responsive display ads take image and text assets and assemble the ad to fit whatever slot is available, which is why the required asset list is short. From Google's responsive display ads specifications:

Google allows one to fifteen images per shape and recommends five of each. The text side is tightly capped: headlines are 30 characters, the long headline is 90, descriptions are 90, and the business name is 25. Those limits matter for banner design because the assembled ad renders your copy as live text over your image, so any words baked into the artwork compete with it.

The practical read: responsive covers reach, fixed sizes buy control. Most advertisers run responsive as the base and add hand-built 300 x 250, 728 x 90, and 160 x 600 units for the placements they care most about.

How to produce a banner set at every size

The hard part of a banner set is not the pixel count, it is that a 320 x 50 strip and a 300 x 600 tower need genuinely different compositions. A design that works at one aspect ratio rarely survives being squeezed into another.

1. Pick the shapes, not the pixel counts. Your set collapses to about five aspect ratios: roughly 6:5 (300 x 250 and 336 x 280), 8:1 (728 x 90), 1:3.75 (160 x 600), 1:2 (300 x 600), and 6.4:1 (320 x 50). Design once per shape, then export to the exact pixel size.
2. Generate the background art per shape. The AI ad banner generator produces banner artwork from a description in square, vertical, story, wide, and ultra-wide ratios, with free trial credits. Generate the closest ratio to your target and crop to the exact dimensions, since the tool works in aspect ratios rather than fixed IAB pixel sizes.
3. Typeset separately. AI image models render lettering unreliably. Generate art with clear space reserved for copy, then add the headline, price, and call to action in Figma, Canva, or Photoshop where you control kerning and can swap the offer without regenerating.
4. Export to weight, not just to size. Under 150KB per image satisfies Google. For programmatic buys, hit the tighter IAB per-unit number: 50 kB initial load for a mobile banner is the constraint that actually bites.
5. Test variations, not just formats. Once the shapes exist, the variable that moves click-through is the creative concept. Ad creative variations generates controlled alternates of the same concept so you are comparing ideas rather than resizes.

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If you want the wider workflow around this, from concept to a full set of placements, the AI ad generator hub covers it, and AI-generated ads goes deeper on where generated creative holds up and where it does not.

Which banner ad sizes actually get served

Inventory is not evenly distributed across the twenty sizes Google accepts. Two structural facts explain the concentration. The IAB narrowed its portfolio deliberately, selecting units that "contribute to the majority of revenue and are sufficient to advertise across multiple screen sizes," which is why its fixed list runs to a dozen entries rather than fifty. And Google's own naming maps its most common slots onto those same shapes.

A defensible starting set, in build order:

• 300 x 250. The most portable unit in display. It fits desktop sidebars, in-article slots, and mobile, which is why it is usually the first and sometimes only banner an advertiser builds.
• 728 x 90. Desktop header and footer inventory. Almost no room for anything but a logo, a short line, and a button.
• 320 x 50. Mobile anchor. The 50 kB IAB initial load budget makes this the hardest unit to make look good; keep it to a mark, four or five words, and a button.
• 300 x 600. The half-page. It occupies more of the screen for longer as the reader scrolls, and it has enough vertical room for a real product shot rather than a logo and a button.
• 160 x 600. The classic sidebar rail. Narrower than the half-page, so treat it as a vertical strip rather than a poster.

Add 970 x 250 and 336 x 280 when the buy justifies them, and skip 468 x 60 and 120 x 600 unless a specific publisher asks. Those two are legacy sizes still accepted by Google but absent from the IAB recommended portfolio.

Banner sizes outside the display network

Paid social and channel art run on entirely separate specs, and mixing them up is the most common reason a banner uploads cropped or soft. If your work spans placements, the exact numbers for the common ones live in these guides:

• Facebook ad sizes for feed, story, and reel placements on Meta.
• Facebook cover photo size for Page cover art and its two device crops.
• YouTube banner size for channel art at 2560 x 1440 and its safe area.
• LinkedIn banner size for the 1584 x 396 profile strip and the 4200 x 700 Page cover.
• Static ads for why a still image still outperforms motion in plenty of placements.

The display spec itself is stable. Google's accepted size list and the IAB fixed portfolio have not moved in years, so a banner set built to those numbers keeps working. The part that goes stale is the creative, which is the argument for making the set cheap to regenerate rather than precious.