What is Fill Rate? 

Fill Rate is the percentage of ad requests served by the ad network. This metric is calculated by dividing the total number of successful ad impressions by the number of requests per impression. The ideal occupancy is 100%, i.e. absolutely all ads that were requested from advertising networks were downloaded and shown. In this case, the coverage of the audience will be maximum. 

For every ad request that doesn’t get filled and every ad not shown to users, publisher and advertiser lose out on potential earnings. That’s why it’s important to make sure fill rates are always high.

Put simply, higher fill rates mean more ad revenue for publishers and advertisers.