Why Should Publishers Care About MRC Ad Viewability?

The Media Rating Council (MRC) sets standards and conducts audits to make digital advertising reliable and effective. As it is an independent organization formulated for the betterment of the industry, 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. 

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 guessed, MRC defined certain thresholds to help ad-tech vendors consider an ad impression viewable. But, before discussing the MRC viewability guidelines, let’s briefly look at the basic concepts in ad viewability:

• Fraudulent or Invalid Impressions
  Fraudulent impressions are illegitimate ad impressions 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 viewable when the ad is in the viewable space of a web browser’s window. If the ad is displayed outside a browser’s viewport, then the ad impression doesn’t have the chance to be seen by a user. 

So, What Is MRC Ad Viewability?

We all know quality content deserves quality advertising. But how do we ensure those ads are actually reaching real eyeballs? With MRC ad viewability. Think of it as the gold standard for making sure advertisers get their money's worth (and you get fairly compensated).

It's pretty straightforward: 50% of a display ad needs to be visible for at least a second, with video ads requiring two continuous seconds. Simple, right? Well, not exactly. There's a bit more to the story when it comes to ad size, pixels, formats, and user interactions.

The bottom line? MRC sets the bar for ensuring your premium content delivers impactful ads. Let’s explore the nitty-gritties involved;

‍MRC Display Ad Viewability

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

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

• A strong interaction between the user and the ad can be considered viewable even if it doesn’t meet the time or pixel requirement. Here, “strong interaction” means a legitimate click should happen from the user’s end. Moving the mouse cursor over the ad wouldn’t be considered 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, a few vendors 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 those extra-large display ads (ads sized at 242,000 pixels, equivalent to 970×250 large display ads or greater), the rules are a bit different. Only 30% of the ad needs to be visible for at least one second to count as a viewable impression.
• Do you know those eye-catching ads that transform from bite-sized to full-blown experiences?  They're called rich media display ads, measuring them can be technical. You need to track their "viewability" based on their size at any given moment. Calculate it as;

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

This means for small, pre-expanded ads, measure view time until expansion. Once expanded, start a new measurement. Add up to total the "view time".

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

‍MRC Video Ad Viewability

‍To count as a video ad impression, at least 50% of the ad’s pixels must be visible in the viewable space of the browser for a minimum of two consecutive seconds. This two-second rule does not only apply to the first two seconds of the video ad. Any unduplicated ad content that lasts for two seconds between videos will also count as an ad impression.

‍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:

1. For Click-To-Play Ads
   Pixel Requirement: At least 50% of the ad's pixels must be viewed. This means at least half of the ad is visible on the user’s screen.
   Time Requirement: This visibility must be maintained for a solid two seconds.
   It’s important to note that this two-second rule applies to any two-second video segment, not just the beginning.
   

2. For Auto-Play Ads
   Auto-play ads adhere to similar MRC viewability standards as click-to-play ads. However, audio must be on for auto-play video ads to be considered viewable. Accurately measuring these ads is complex, making reliable measurement partners crucial.By meeting these standards, you can deliver higher-quality ad inventory, boost advertiser confidence, and ultimately drive more revenue.

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 follows:

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

• Impression Distribution
  Impression distribution represents the percentage of viewable, non-viewable, and undetermined ad impressions.
  
  
• Number of Impressions in Category / Total Impressions X 100 = Percentage

These performance metrics help 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 accurately measure 100% ad viewability.

Wrapping Up

Viewability is among the major challenges publishers, and advertisers encounter 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.

In recent advancements, the Media Rating Council (MRC), in collaboration with the Interactive Advertising Bureau (IAB), finalized the Attention Measurement Guidelines in November 2025. These guidelines build directly on established MRC viewability standards, requiring ads to first meet core viewability thresholds (such as the 50% pixels for 1 second for display or 2 seconds for video) as a foundational baseline before applying attention signals.
This framework introduces standardized approaches, including data signal-based, visual tracking, physiological/neurological, and panel/survey methods, to measure not just if an ad was viewable, but the degree to which it captured genuine user attention, enabling more consistent evaluation of ad quality and performance across digital and cross-media environments.

Still, have questions about ad viewability standards? Connect with us and we’ll help you find their answers.