What is impression share in Google Ads?
WeAdU · Updated 3 October 2026
Impression share is the percentage of impressions recorded out of the eligible impressions. It is not CTR, which compares clicks with impressions already received.
How does the help define eligible impressions?
Google Ads help, read on 3 October 2026, defines impression share as impressions recorded divided by eligible impressions. CTR compares clicks with impressions already received. The two ratios do not stand in for each other. A label that would mean a surcharge is not this metric.
Two help pages diverge on what makes an impression eligible. One cites targeting, approval and quality. The other adds bids and ads that are already running. You read it at campaign, ad group, keyword, and Shopping product group. A dash is shown when the data is missing. Google Search partner sites are not included in this rate.
What do budget and rank separate?
Budget and rank are two columns of lost impressions, not one figure. Budget is read at the campaign. Lost impressions for budget on Search and those on Display are not added together. Exact-match keywords do not have this rate in Shopping. When the budget is exhausted, rank does not appear in ad groups. Refresh intervals cited by the help are not copied here.
Reading the rate without those columns mixes two causes. An impression lost to budget means the campaign could have participated and the budget ran out. An impression lost to rank means the ad was not chosen against the others. The help keeps them apart. It does not ask you to add them from one inventory to another.
How do Shopping and Performance Max count?
Several Shopping ads from the same advertiser can show together. Each one receives an impression. The rate keeps only the best-ranked one. If that ad is the most prominent, it also counts in absolute top impression share. Shopping follows Search, not Display. Performance Max adds Search and Shopping, in the numerator and in the denominator. Shopping does not borrow the Display definition. Performance Max, adding Search and Shopping on both sides of the ratio, is not read as a Search campaign alone, or as a Shopping campaign alone. The dash, when data is missing, is not a rate: it is missing data.
What does the WeAdU audit cover?
The homepage, reread on 3 October 2026, says: "The free audit covers Google Ads only." This page defines the rate. It produces no figure for an advertiser, and it does not promise an impression share.
Help pages
Google help pages read on 3 October 2026.