What are the standard IAB ad sizes, and which ones does a plan need?
Part of Programmatic media planning
The short answer
IAB ad sizes are the display dimensions the industry builds creative and ad slots around, such as the 300x250 medium rectangle, 728x90 leaderboard, 160x600 skyscraper, 300x600 half page, 970x250 billboard and 320x50 smartphone banner. The IAB New Ad Portfolio of 2017 kept these as fixed sizes and added flexible units defined by aspect ratio.
Key takeaways
- The IAB New Standard Ad Unit Portfolio, version 1.1 of July 2017, recommends a short list of fixed sizes chosen by which units contribute to the majority of revenue.
- The portfolio also defines flexible units by aspect ratio with a minimum and maximum size, so one ad can adjust to the screen.
- Google's publisher help lists 300x250 among top performing sizes for both desktop and mobile and describes 320x50 as filling the width of a mobile phone screen.
- A site can only serve a campaign in sizes it has slots for, so a narrow size list quietly shrinks the set of eligible sites.
- A media plan should list every size by device, with the file weight limits and the sites that carry each one.
What are the standard IAB ad sizes?
Definition
- IAB ad size
- A display ad dimension, written as width by height in pixels, that IAB guidelines recommend so that creative built once can run on many publishers' ad slots.
The current reference is IAB Tech Lab's New Standard Ad Unit Portfolio (opens in a new tab), version 1.1 of July 2017, and its companion fixed size ad specifications (opens in a new tab). The fixed list was chosen from an attitudes and usage study to find which of the ad units contribute to the majority of revenue and are sufficient to advertise across multiple screen sizes. The file weights below are IAB's recommended maximums after gzip compression, split into the initial load and a later subload.
| Ad unit name | Size (pixels) | Initial load, max | Subload, max | Typical position |
|---|---|---|---|---|
| Medium Rectangle | 300x250 | 150 kB | 300 kB | Inside or after article text, side rail |
| Leaderboard | 728x90 | 150 kB | 300 kB | Above the main content on desktop |
| Skyscraper | 160x600 | 150 kB | 300 kB | Side rail on desktop |
| Smartphone Banner | 300x50 or 320x50 | 50 kB | 100 kB | Top or bottom of a phone screen |
| Billboard | 970x250 | 250 kB | 500 kB | Above the main content on wide screens |
| Super Leaderboard or Pushdown | 970x90 | 200 kB | 400 kB | Top of page on desktop; the pushdown version moves content down |
| Portrait | 300x1050 | 250 kB | 500 kB | Beside content on wide screens |
| Mobile Phone Interstitial | 640x1136, 750x1334 or 1080x1920 | 300 kB | 600 kB | Full screen on phones |
The 300x600 half page is not on the fixed list, but the portfolio names it as the transition size for its 1x2 vertical unit, with 200 kB initial and 400 kB subload, and Google's publisher help calls it one of the fastest growing sizes by impressions. The fixed list also keeps the 120x60 unit and three tiny feature phone banners, which a North American plan may not need.
What is the IAB New Ad Portfolio?
The portfolio was developed by the IAB Tech Lab Flex Ads Committee after a public comment draft in September 2016. It covers display ads, native ads and newer formats such as 360 degree, virtual reality and augmented reality ads, and it makes two changes that matter to buyers: LEAN principles and flexible sizing.
| Change | What the portfolio says | What it means for a buyer |
|---|---|---|
| LEAN ads | Light, Encrypted, AdChoices supported, Non-invasive; at most 10 file requests in the initial load; audio muted unless the user starts it | Creative has a weight budget per size, and heavy files may be rejected by publishers that enforce it |
| Flexible sizing | Units defined by aspect ratio with a minimum and maximum size in density independent pixels, so the ad adjusts to the screen | A 1:1 tile can run from 300x300 to 450x450 dp; creative must scale without losing its message |
| Transition sizes | Each flexible unit names the old fixed size closest to it, such as 300x250 for the 1:1 tile and 728x90 for the 8:1 unit | Existing fixed size creative still maps onto the new grid |
| Availability | The guidelines are an industry recommendation, and not all publishers adopt them without modification | Check each publisher's own specs before production |
Flexible sizes reach the bid request through OpenRTB. In OpenRTB 2.6 (opens in a new tab) the Banner object carries a format array of the banner sizes permitted, and each Format object holds either a fixed w and h in device independent pixels or the Flex Ad set of wratio, hratio and wmin. A DSP compares those sizes with the creative it holds; an impression that offers only sizes the campaign lacks gets no bid.
Which ad sizes have the widest reach on mobile?
No public standard ranks sizes by mobile reach, but publisher documentation shows which sizes phone pages are built around. Google's AdSense guide to ad sizes (opens in a new tab) marks 300x250 as supported for mobile text and display ads and says it tends to have more ad inventory available from advertisers. It describes 320x100 as the large mobile banner, which can be used in place of the 320x50 or the 300x250, and 320x50 as a mobile optimized banner that works well at the bottom of a page.
The Google Ad Manager list of supported sizes (opens in a new tab) adds that 320x50 ads fill the width of a mobile phone screen, that 300x50 fits larger phone screens at the top or bottom, and that some ad slots expand automatically to the maximum width allowed on a device, which applies to backfill display and non in-stream video slots on mobile web. A mobile set built from 300x250, 320x50 and 320x100 covers the slots these documents describe; 300x600 adds a larger unit for sites that carry it.
How do ad sizes affect which sites can serve a campaign?
A site can only show an ad in a slot it has built. One publisher may run a single 300x250 in the article and a phone banner, while another adds billboards, half pages and portraits. Every size dropped from the creative set removes some sites and slots from the campaign, and the delivery report may not say why it is thin.
Large formats need a supply check. Google's AdSense guide says advertiser demand for larger formats is on the rise but the supply of available display ads for 970x250 and 300x1050 is currently limited, and Ad Manager notes high demand for 970x250 in preferred deals and private auctions. A billboard only campaign will run on fewer sites than its site list suggests. For the slot side, see the guide to what an ad server does, and for how many units a page should carry, see ad density.
How should creative sizes be listed in a media plan?
Put the size list in the plan itself, not only in the creative brief, so the buyer, the creative team and the client approve the same set. Record size, device, language versions and the file weight cap the creative must meet.
Creative size section of a media plan
- Each line names the sizes it buys and the device each size is meant for.
- Every size has a file weight cap, from the publisher's specs where they exist and IAB's maximums otherwise.
- Mobile lines include 300x250 and at least one phone banner, 320x50 or 320x100.
- Large formats such as 970x250 or 300x1050 are listed with the sites known to carry them.
- Each language version of the creative exists in every listed size.
- Flexible or responsive units name the aspect ratios and minimum sizes the creative supports.
If the campaign also runs through Google's Display Network, note which lines use uploaded image ads and which use responsive display ads. Google's responsive display ads help (opens in a new tab) calls them the default ad type for the Display Network and says they automatically adjust size, appearance and format to fit just about any available ad space, while static image ads include images as you originally provided them.
How does PlacementGraph connect the site list to ad formats?
What does a size plan look like for a bilingual brief?
Fictional example
A hardware store cooperative in New Brunswick
A fictional cooperative of independent hardware stores in Moncton, Bathurst and Edmundston, New Brunswick, plans a fall display flight on home repair content in English and French. The first creative brief lists only 728x90 and 970x250, the sizes from last year's desktop campaign.
The planner checks the approved site list and finds that most of the French language community sites carry only a 300x250 and a mobile banner. The plan adds 300x250, 320x50 and 320x100 for phones and keeps 970x250 for the three regional news sites that sell it.
The French copy runs longer than the English, so the creative team writes a shorter French headline for the 320x50 rather than shrinking the type. The plan's size table lists each size, device, language version, file weight cap and the sites that carry it.
Frequently asked questions
What is the most common display ad size?
No public census ranks sizes, but Google's AdSense and Ad Manager help both list the 300x250 medium rectangle among top performing sizes and say it tends to have more ad inventory available from advertisers. The IAB New Ad Portfolio names it as the transition size for its 1:1 tile.
Do ad sizes use pixels or density independent pixels?
Both, depending on the document. The IAB fixed sizes are written in pixels, while the flexible units use density independent pixels, which IAB describes as a way to measure an image consistently regardless of screen resolution. OpenRTB banner sizes are given in device independent pixels, so a 320x50 slot on a high density phone needs a sharper image file.
Are skyscraper and leaderboard sizes still worth including?
On desktop, yes, where sites carry them. Google's publisher help says 728x90 and 160x600 tend to have more ad inventory available from advertisers, while the narrower 120x600 has more limited supply. Neither fits a phone in portrait, so keep them on desktop lines only.
Does one creative file work across all sizes?
A static image does not; each size needs its own file within its weight cap. HTML5 creative built on the portfolio's flexible units can scale within an aspect ratio, and responsive display ads in Google Ads are assembled from assets to fit the slot. Neither replaces checking each publisher's specs.
Sources
- IAB New Standard Ad Unit Portfolio, version 1.1 (July 2017) (opens in a new tab)IAB Tech Lab
- IAB New Ad Portfolio: Fixed Size Ad Specifications (opens in a new tab)IAB Tech Lab
- OpenRTB 2.6 specification, Object: Banner and Object: Format (opens in a new tab)IAB Tech Lab on GitHub
- Guide to ad sizes (opens in a new tab)Google AdSense Help
- Supported ad sizes (opens in a new tab)Google Ad Manager Help
- About common sizes for responsive display ads (opens in a new tab)Google Ads Help
Researched and written by PlacementGraph Research. Read how we research, source and update these pages. Corrections: diana@placementgraph.com.