Impression Share is the percentage of eligible impressions an ad received compared with the total impressions it could have received. A common calculation is: Impressions received ÷ eligible impressions.
In practical google ads work, the important question is not just what Impression Share means, but how it should influence decisions. It matters because paid search can spend budget quickly. Knowing this term helps teams control intent, targeting, bidding, creative, conversion tracking, and lead quality instead of optimizing for surface-level clicks.
A strong approach should connect Impression Share to measurable outcomes such as qualified traffic, calls, form submissions, booked appointments, ecommerce revenue, or lower acquisition costs.
Example
In a Google Ads account for website design leads, impression share might determine how campaigns are structured, how budget is spent, how ads match search intent, and how conversions are measured. A strong setup would connect ad clicks to form submissions, phone calls, lead quality, and actual sales outcomes.