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Viewability Measurement with Adnami

Our guide on viewability measurement. In this article, we will explore how Adnami implements viewability measurement, aligning with the standards set by the IAB and MRC.

Viewability Basics:

Viewability is the ratio of [viewable ad impressions] to [all ad impressions] and provides insight into the percentage of impressions that are viewable from a given media buy. The IAB has outlined specific criteria for defining a viewable impression, some of the basics include:

  • Pixel Requirement: At least 50% of the pixels in the advertisement must be on an in-focus browser tab within the viewable space of the browser page.
  • Time Requirement: The time the pixel requirement is met should be greater than or equal to one continuous second, post ad render.

The full IAB specifications can be found here: https://www.iab.com/wp-content/uploads/2015/06/MRC-Viewable-Ad-Impression-Measurement-Guideline.pdf


All Ad Impressions:

An ad impression is triggered when the Adnami <ins> tag is loaded onto a webpage. This includes both rendered and non-rendered impressions.

High Impact Ads:

For large-sized display ads on desktop, additional specifications come into play. If an ad exceeds 242.500 pixels (equivalent to a 970x250 display banner), the pixel requirement is reduced to 30%. This means that viewability for most high impact formats from Adnami is triggered after 30% of the ad has been in view for at least 1 second.

Desktop vs. Mobile Considerations:

The IAB/MRC definition primarily caters to desktop usage however, with the significant rise of mobile since the document's release in 2014, adjustments are necessary. While there are no specific guidelines for large size ads on mobile (see notes on page one in aforementioned link), Adnami has chosen to mirror the desktop guideline by replacing the 970x250 banner size threshold with 320x480 for mobile. (a format typically used for mobile interstitials). Recognising the distinct experiences of mobile and desktop users, we believe that the 320x480 size best represents the purpose of the viewability definition in the absence of a shared definition for large ads on mobile.

As a result, the threshold for the 30% in-view measurement on mobile is set at 153.600 pixels, for all banners smaller will apply the 50% in-view limit. 

On mobile, a large-sized ad is triggered when more than 46% of the viewport is covered by the ad, compared to 12% on desktop. 

Banner Formats with Special Properties:

HorseShoe Shaped Ads (Skins):

Skins, consisting of two vertical rectangles on each side of the screen and one horizontally aligned banner in the center top, pose challenges for viewability measurement. Adnami measures on the vertically aligned element, considering it the best representation of a viewable impression. Variations may occur when comparing numbers between Adnami and other systems that do not apply this method.


The Midscroll format "cuts a hole" in the website and displays in a larger banner within the cutout on the website. It triggers viewability when the hole in the website takes up 30% of the screen. The measurement does not occur on the asset "behind” the website.

Anchor Ads:

Some banners, like anchor formats which combine Midscroll with a small display ad, consist of discrete elements. Adnami measures a viewable impression when at least one of the elements meets the criteria of either 30% or 50% in view, depending on the size of the creative element.



Our Commitment:

At Adnami we constantly strive to provide the best measurement and metrics to aid in both understanding and optimising media trading. We believe in full transparency and encourage open discussion of how and what we measure to empower our users.