Impression Share, often abbreviated as IS, is a metric used in digital marketing to represent the percentage of impressions that your ads receive compared to the total number of impressions that your ads could potentially receive. It is a key performance indicator that helps advertisers understand how effectively their ads are reaching their target audience within a given competitive landscape. The formula for calculating Impression Share is the number of impressions your ad received divided by the total eligible impressions in the market for the specified criteria, such as keywords, location, and targeting settings.
For example, if your ad could have been shown 100 times based on the search queries matching your keywords, but it was only shown 80 times, your Impression Share would be 80%. A lower Impression Share might indicate that there’s room for improvement in your campaign settings, bid strategy, or budget allocation. Conversely, a high Impression Share suggests that your ads are capturing a significant portion of the available visibility for your targeted criteria. Understanding and optimizing for Impression Share can help advertisers maximize their visibility and impact within their target market.