Ad Impression Share in Google Ads

Ad Impression Share in Google Ads

Ad Impression Share shows the percentage of impressions that a Google Ad receives compared to the total number of eligible impressions

Definition of Ad Impression Share

Ad Impression Share is a metric that quantifies the percentage of impressions that an advertiser’s ad receives compared to the total number of eligible impressions.

It’s a representation of the advert’s visibility within a particular market or for specific keywords.  A higher impression share indicates that the ad is being shown frequently to users searching for the relevant terms.

For example, if a campaign has an impression share of 80%, it means that the ad is being displayed 80% of the time when it is eligible to be shown.  The remaining 20% represents missed opportunities where the ad wasn’t displayed due to various factors.

Understanding the Calculation of Ad Impression Share

The formula to calculate Ad Impression Share is straightforward:

Formula for ad impression share



  • Number of Ad Impressions: The actual number of times the ad was displayed to users.
  • Total Eligible Ad Impressions: The total possible impressions the ad could have received based on its targeting settings, bid strategy, and quality score.

By applying this formula, advertisers can obtain the percentage of times their ad was shown in relation to the potential times it could have been shown.

Significance of Ad Impression Share

  1. Visibility and Brand Awareness: A high Ad Impression Share indicates that the ad is being frequently displayed, improving brand visibility and awareness.  People are more likely to remember and consider a brand they encounter more often.
  2. Competitive Insights: Monitoring Ad Impression Share allows advertisers to assess their performance in comparison to competitors.  A lower impression share than competitors could signal the need for strategy adjustments to enhance visibility and competitiveness.
  3. Identifying Growth Opportunities: If there’s room for improvement in impression share, it suggests potential growth opportunities.  By optimising campaigns and targeting, advertisers can aim for a larger share of ad impressions.
  4. Efficiency in Ad Spend: Ad Impression Share helps in efficient budget allocation.  A high impression share indicates that the budget is being utilised effectively to capture a significant portion of the available impressions.

Factors Influencing Ad Impression Share

Several factors impact an ad’s impression share:

  1. Budget: The daily budget allocated for the campaign affects how often the ad can be shown.  A higher budget generally leads to a higher impression share.
  2. Bid Competitiveness: The bid amount influences ad placement and visibility.  A competitive bid increases the chances of the ad being displayed.
  3. Ad Relevance: The relevance of the ad to the search query and the selected keywords directly impacts impression share.  Highly relevant ads are more likely to secure a higher share.
  4. Quality Score: Ads with a high quality score, determined by relevance, ad copy, and landing page experience, are favoured by the Google Ads algorithm, resulting in a higher impression share.

Strategies to Improve Ad Impression Share

  1. Optimise Bids: Adjust bidding strategies to be more competitive, especially for high-value keywords, to improve ad placement and increase impression share.
  2. Enhance Ad Relevance: Craft targeted ad copies and choose keywords that closely align with the ad content.  This increases the ad’s relevance and boosts impression share.
  3. Expand Targeting: Broaden the target audience or geographic reach to tap into more potential impressions, increasing the ad’s exposure.
  4. Monitor Competitors: Analyse competitor strategies and adjust bidding and targeting to remain competitive and improve impression share.

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