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What Is Ad Viewability

Viewability is a metric, given as a percentage, used in the mobile advertising space to express how visible ads are to users on a mobile device.

There is still some inconsistency when it comes to defining the criteria of a “viewable impression;” the International Advertising Bureau (IAB) and Media Rating Council (MRC) defines it as when a certain percentage of the ad is visible to the user for a minimum time frame.
Key Takeaways
  • An ad is considered viewable when a certain percentage of it is visible to a mobile user for a minimum time frame
  • Ad viewability can be used as a goal for advertisers or as a pricing model (vCPM)
  • Benchmarks for a high viewability rate depends on the ad format, target region, and standards within that vertical

How Does Viewability Work?

For mobile display ads to be considered “viewable” to a user, at least 50 percent of the ad’s pixels must appear on a user’s phone screen for at least a second. Video ads must be viewable for at least two seconds.

This definition of a viewable impression has been suggested by the IAB and Media Rating Council (MRC).

The formula for calculating viewability is as follows:

Viewability is the total viewable ad impressions divided by the total ad impressions served. You then take this number and multiply it by 100.

Viewability is typically used as a goal or benchmark for mobile advertisers and demand-side partners, who want to optimize their UA budgets and pay for impressions that are measured as viewable.

What Affects Viewability?

There are various factors that influence mobile ad viewability.

These include:

  • The speed at which the ad loads: this is influenced by mobile connection
  • Ad placement: where an ad is place inside an app
  • Ad size and format: interstitials that take up an entire mobile screen generally have better viewability rates
  • Ad fraud: fraudulent traffic can inflate views and thus viewability rate artificially 

To optimize their viewability rate, mobile publishers should analyze these data points. They might decide, for example, to place banner ads in an app’s home screen to increase the number of users who see the ad – and therefore the number of users they can monetize.

It is, however, crucial that publishers at the same time prioritize mobile user experience – the revenue they generate through high viewability rates should not come at the cost of a positive user experience. Users will otherwise churn from the app if they are served irrelevant and spammy ads that disrupt their in-app experience. 

Benchmarks for what is considered a high viewability rate depends on the ad format, target region, and standards within that vertical. 

Why Is Viewability Important?

Publishers and mobile advertisers should monitor viewable ad impressions to improve their KPIs. 

Advertisers benefit from:

  • better brand awareness
  • more installs
  • better understanding of the effectiveness of their campaigns – are they investing in inventory that boosts their KPIs?
  • less unnecessary UA budget spending

Ad viewability measures a brand’s opportunity to be seen; however, advertisers should also focus on effective targeting and creative output to ensure maximum campaign success. 

Advertisers who enjoy high ad viewability – perhaps by targeting apps with high daily active users – observe higher ROAS in their campaigns. Publishers benefit from this because these advertisers are willing to pay more for these premium ad placements.

Publishers with positive viewability metrics benefit from:

  • being able to demand higher prices for their ad inventory/increase the value of their ad inventory
  • maximized ad revenue

They can also optimize their apps by tracking and identifying high and low areas of viewability inside the app.


Mobile ad viewability will continue to be an important metric for both advertisers and publishers. In fact, it will only grow in importance. 

That’s because this KPI offers UA teams valuable insights into their campaign effectiveness and how to spend their UA budget effectively. All the while, mobile publishers can enhance revenue generation by offering advertisers high viewability rates – and continuously optimizing them.

What Is Ad Viewability?

Mobile ad viewability tells you how visible ads are to users on a mobile device.  For an ad to be considered viewable, the ad content must be within the viewable region of the browser or app for a minimum period of time.

How Do You Calculate Viewability?

Viewability is the total viewable impressions divided by the total ad impressions served. You then take this number and multiply it by 100.

Why Is Viewability Important?

Mobile advertisers benefit from better brand awareness, more installs, a better understanding of how effective their campaigns and UA spending are. Publishers can use high viewability performance to sell their ad inventory at higher prices and maximize their revenue.

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