Banner ad sizes
The single highest-inventory size: it fits desktop sidebars and in-article mobile slots alike. 150 kB in the IAB portfolio too, so the two agree here.
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Three sizes carry most display inventory: the medium rectangle at 300 × 250, the leaderboard at 728 × 90 and the mobile banner at 320 × 50. Google Ads caps every image ad at 150 KB whatever its size, and since most display creative is trafficked through Google that flat number is what shapes how banners look. The IAB’s own portfolio is not flat: it allows 250 kB for a billboard and only 50 for a mobile banner.
How to use the banner ad sizes
The IAB publishes a long list and the market ignores most of it. Inventory concentrates heavily in a few shapes because those are what publishers actually template into their layouts, and building the tail sizes rarely repays the effort. If you build only two, build the 300 × 250 and the 320 × 50: the first is eligible for more slots than any other size because it fits both a desktop sidebar and an in-article mobile placement, and the second is where the impressions now are. The billboard at 970 × 250 is the exception worth adding: a premium above-the-fold placement on larger sites, higher rates, and a genuinely different design problem from the small formats. The two vertical formats are worth reading together. A skyscraper is 160 pixels wide, which fits a logo and a stacked line or two and nothing else, while the half page at 300 × 600 occupies the same slot on many layouts with nearly twice the area, so check whether the placement accepts it before committing to the narrow one. Both are desktop-only, because sidebars mostly do not exist on a phone.
Whose 150 KB it is
The weight limit gets attributed to the IAB constantly, including by people trafficking against it, and it is not theirs. 150 KB flat, every size, is Google Ads. That is the number this page checks your file against, because it is the one most display creative actually has to clear. The IAB portfolio is per-unit and disagrees with it in both directions: a billboard at 970 × 250 is allowed 250 kB and a 970 × 90 is allowed 200, while a smartphone banner at 320 × 50 or 300 × 50 is held to 50 kB — a third of what Google permits. The medium rectangle, the leaderboard and the 160 × 600 skyscraper are the sizes where the two happen to agree at 150. So a 140 KB mobile banner passes the check on this page and passes Google, and would still be three times over spec for a publisher working to the IAB portfolio; a 200 KB billboard fails here and is within the portfolio. Read the note on each row for the unit where it matters. Either way the limit rules out photographic backgrounds at these dimensions and pushes designs toward flat colour and type, which is why display advertising looks the way it does.
Paid social sits beside all of this and obeys almost none of it. There is no weight cap of that order and no fixed pixel box: a feed unit is 1080 × 1080, or 1080 × 1350 when you want more scroll height, a story or a Reel is 1080 × 1920, and a link-card placement takes the same 1200 × 628 an Open Graph image uses. Those frames are on this page because the same campaign nearly always needs both halves, and briefing them separately is how a set ends up inconsistent. What replaces the weight limit there is interface. A vertical unit carries the account row across the top and the caption and call to action across the bottom, with a rail of buttons down the right on TikTok, so the canvas is 1080 × 1920 but the part anyone reads is the band in the middle. TikTok publishes a safe area for an in-feed ad and the zone drawn on that frame follows it. The Meta frames are measured from the interface instead, because what Meta publishes is a reserved band at each end rather than a percentage, so treat those as close rather than exact and leave a little margin. TikTok takes more either way, which is why the two frames do not match.
What people use it for
- Picking the two or three banner sizes worth building first
- Exporting a Google display set at 300 × 250, 728 × 90, 160 × 600, 320 × 50 and 300 × 600
- Checking a leaderboard design against the 728 × 90 frame and its mobile replacement
- Deciding between a 160 × 600 skyscraper and a 300 × 600 half page
- Checking creative against Google’s flat 150 KB before trafficking it
- Finding the sizes where the IAB’s per-unit weight is not 150 KB
- Cutting the paid social half of a campaign to the same brief as the display half
- Keeping a story or Reel unit clear of the caption and the button rail
Questions
The 300 × 250 and the 320 × 50. Between them they cover most inventory across desktop and mobile. Add the 728 × 90 next, then the 300 × 600 and the 970 × 250 if there is budget for them.
It depends whose limit you mean. Google Ads caps every image ad at 150 KB regardless of size, and that is the number this page checks against. The IAB portfolio is per-unit: 250 kB for a 970 × 250 billboard, 200 for a 970 × 90, 150 for a 300 × 250, a 728 × 90 or a 160 × 600, and only 50 for a 320 × 50 or 300 × 50 smartphone banner. Paid social has no equivalent cap at all.
No, and this is the most repeated mistake about display specs. The flat 150 KB is Google’s. The IAB sets a different weight for each unit, and for a mobile banner it is three times stricter.
It fits desktop sidebars and in-article mobile placements, so it is eligible for far more slots than any other size. It is also one of the first units an AdSense or Ad Manager tag will fill on a page that offers several.
728 × 90. It is a desktop format and does not fit a phone at all, which is why the 320 × 50 mobile leaderboard exists.
160 × 600 for the wide version. The older 120 × 600 still exists but is largely superseded.
Usually. At 300 × 600 it fits many of the same slots with nearly twice the area.
No, they are sidebar formats and a phone layout mostly has no sidebar. The tall unit that does run on mobile is the 320 × 100 large banner.
1080 × 1080 for a feed square, 1080 × 1350 for more scroll height, 1080 × 1920 for a story or a Reel, and 1200 × 628 where the placement renders a link card. Those frames are on this page too, since a campaign usually needs both halves.
970 × 250, a premium above-the-fold desktop placement that typically commands higher rates.
The Interactive Advertising Bureau, which publishes the standard ad formats publishers and networks template against.
No. The tail sizes get very little inventory relative to the effort of building them.
PNG for flat colour and text, which is most display creative. JPEG only if the ad is genuinely photographic.
A logo, one short line and a button. Anything more is illegible.
Sometimes, but the weight limit is unchanged, which severely constrains how much animation fits.