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MRC Viewability Standards – A Quick Reference Guide

MRC Viewability
So, how do you know if your ads are deemed as 'viewable'?

Almost six years ago, the Media Rating Council (MRC) set standards and conducted audits to make digital advertising reliable and effective. As it is an independent organization formulated for the betterment of the industry as a whole, the players in the adtech ecosystem confer and agree with the MRC viewability standards. To give you an overview, MRC viewability is a standard introduced to determine whether an ad impression is viewable or not. 

Ad viewability is not a new concept in the ad tech industry. But when both publishers and advertisers began to realize the impact of viewability on their bottom lines, it became apparent to feel the need for standard guidelines to deem an impression as viewable. 

So, as you have guessed, MRC defined certain thresholds to help ad-tech vendors to consider an ad impression as viewable. But, before talking about the MRC viewability guidelines, let’s have a brief look at the basic concepts in the context of ad viewability:

Fraudulent or Invalid Impressions: Fraudulent impressions are the illegitimate ad impressions that are typically generated with the help of botnets, artificially manipulated page loads, etc. The idea is to siphon the ad dollars from the buyers with invalid traffic (IVT).

Viewable Ad Impressions: An ad impression will be considered as a viewable one when the ad is contained in the viewable space of a web browser’s window. If the ad is getting displayed outside the viewport of a browser, then the ad impression didn’t have the chance to be seen by a user.

Table of Content

So, what is MRC Ad Viewability?

MRC Display Ad Viewability

According to MRC, a display ad will be considered as “viewable” if 50% of the ad creative is visible for at least one second in the viewable space of the browser.

MRC viewability definition

In addition to the above standard MRC viewability definition, an impression can be counted as viewable if the following requirements are met:

  • If there is a strong interaction between the user and ad, then the ad can be considered viewable even if it doesn’t meet the time or pixel requirement. Here, “strong interaction” means that a legitimate click should happen from the user’s end. Moving the mouse cursor over the ad wouldn’t be considered as an impression.
  • Usually, viewability vendors calculate the number of viewable impressions based on the ad itself (by adding a JS tag to the code). However, there are a few vendors who calculate the impressions by measuring the ad container (i.e IFRAME) in which an ad appears. In such a scenario, ad-container-based measurement is also acceptable provided that the ad appears in the container in its intended format. 
  • For large display ads sized at 242,000 pixels (equivalent to 970×250 large display ads) or greater, if 30% of the pixels in the ad are visible on the viewport of the web page for more than a second, then it can be counted as a viewable impression.
  • In the case of rich media display ads (which initially appears as one small size ad and then expands based on user-action or time), viewability is measured on the basis of the pixel count of a smaller format of the ad or the expanded format of the ad for the duration when the respective ad format is in place. For the former case (when the ad is viewable prior to the expansion), ad view time will be:

Ad view time in total = Ad view time in-pre expansion state + Ad view time in the expanded state

           If the ad is declared to be viewable for the expanded state, then the ad view time should only count the time when the ad was viewable in the expanded state.

  • If the pages of a website are pre-fetched or pre-rendered, the ads delivered to such pages should not be considered as viewable ads until the ads appear in the viewable section of the browser and follow the conditions specified above.

MRC Video Ad Viewability

A video ad impression will be counted if 50% of the pixels of the ad are visible in the viewable space of the browser for at least two continuous seconds. However, it is not mandatory that the two seconds will only be counted for the first two seconds of a video ad. Any unduplicated content of the ad comprising two seconds in between of the video makes an ad viewable as one.

Other considerations for video ad viewability

Video ad viewability guidelines are similar to the display ad impressions standards. However, there are a few conditions that meet the MRC video ad viewability criteria:

  • For Click-to-Play video ads, if a video ad is initiated by a click and at least 50% of the ad is in view for the first 200 milliseconds, then the impression would be counted as a viewable video ad impression.
  • For Auto-Play video ads, it becomes harder for measurement partners to detect if the auto-play ad was viewable since its execution. Therefore, it is up to the third party to measure and report appropriately.

What are the metrics used in defining MRC ad viewability?

To help the measurement partners, publishers, and advertisers in measuring the impressions count, MRC has defined three metrics :

  • Measured Rate – Measured Rate is represented in percentage and can be calculated as:

Measured Rate = Viewable Impressions + Non-viewable Impressions / Total Served Impressions

  • Viewable Rate – Similar to the Measured Rate, Viewable Rate is the percentage value that can be calculated as follows:

Viewable Rate = Viewable Impressions / Viewable Impressions + Non-viewable Impressions

  • Impression Distribution – Impression distribution represents the percentage of viewable, non-viewable, and undetermined ad impressions.

These performance metrics help the organizations to measure ad viewability rates and detect how many impressions are viewable and non-viewable. Although MRC has defined a few metrics to identify and measure valid impressions, it’s difficult for measurement vendors to measure 100% ad viewability with accuracy.

Now that you know the MRC Viewability Standards, it is time to understand how to improve your ad viewability (and ad revenue)


Viewability is amongst the major challenges publishers and advertisers come across while selling and buying advertisements. However, the Media Rating Council has resolved various issues related to the ambiguity in ad viewability by giving a standard definition for the viewability metric.

Also, many publishers today are offering 100% ad viewability in order to provide better exposure to their advertisers, it is suggested to follow maintain at least 70% ad viewability to ensure better CPMs. With the current competitive landscape, 50 percent wouldn’t able to get you the best possible ad revenue.  

Automatad Team

At Automatad, we help publishers to monetize better without hampering the user experience. Our products are live across hundreds of publishers, earning them incremental ad revenue with every passing second. You can request a free audit to get an estimated revenue uplift today.

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