How many ad calls can Google Ad Exchange fill?

Ad Exchange Ad Optimization
Last updated: August 7, 2020 | by Kean Graham
How many ad calls can Google Ad Exchange fill_

This post was most recently updated on August 7th, 2020

We’ve seen some publishers mention that they can’t get Google Ad Exchange (AdX) to fill their ad slots when they have more than five ad calls per page.

When they attempt to do more than five ad calls from AdX, they receive the following error:

“googletag.defineSlot was called without a matching googletag.display call” and the ads don’t populate.

In this post, we’re going to take a closer look at this error and help you solve it.

When trafficking ads from Google Ad Exchange, there is a system limitation that prevents more than five ads per page from showing. It’s not a new policy. We published an article about it a few years ago that you can read over here.

If you are running into this issue and ads aren’t populating, there are some options you can consider. Limiting the number of ads per page to five ad slots for AdX or less would be one option, although not ideal.

A better option would be to add more demand partners that can compete with Ad Exchange and fill ad slots Ad Exchange isn’t able to. As an example, you can enable header bidding and it competes with Ad Exchange and AdSense. You can find out more about how our header bidding solution, PubGuru Header Bidding, works, and can help increase your RPMs here.

There are lots of other ad networks that you can join to increase competition in your ad stack and improve fill rates that we’ve mentioned here.

When it comes to limits on AdSense ads, you can show as many ads as you want per page. However, it would be best to keep their ad density policies in mind so that you don’t risk your ad account. We discuss how many AdSense ads to show on a page here.


As you can see, solving the Ad Exchange ad call limit isn’t impossible and can even lead to more ad revenue. If you’re experiencing similar problems and don’t know exactly how to add new ad networks, set up header bidding, or make sure that you never show blank ads ever again (every publisher’s situation is different), let MonetizeMore help! Our ad ops experts will ensure your ads are near a 100% fill and help you maximize your ad revenue! Sign up and get started today!

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