Understanding Impression Share

February 05, 2019

Competition in SEM is fierce. Understanding impression share and what all it means can help show you areas in which the competition is beating you. In this blog I’ll be going over what impression share is as well as some other competitive metrics that Google gives you.

Impression Share

You can find impression share in the Google Ads UI under the competitive metrics section when customizing your columns. This metric can be seen at the campaign, ad group, product group (for shopping), and keyword level.

Now what exactly is impression share (IS)? Impression share is defined as the total impressions your ads actually received divided by the total amount of impressions your ads were eligible for.

Impression Share (%) = Impressions / Total Eligible Impressions

Eligible impressions are impressions in which your ads were eligible AND competitive enough for in an auction. These are constrained by many factors including targeting settings, approval statuses, bid, budget, and quality score. In the case of the bid, eligible impressions will include auctions in which your ad could show at twice your bid but exclude auctions in which you would need 1,000% increase your bid.

Search Top Impression Share

Search top impression share is calculated by taking the impressions you received in the top position of the SERPs, divided by by the total amount of impressions your ads were eligible for at the top position of the SERPs. The top position of the SERPs is any ad that appears above the organic results. These are constrained by the same factors noted above for impression share.

Search Top Impression Share (%) = Top Impressions / Total Eligible Top Impressions 

This metric can help you bid to target the top of the page. Although, Google now as a bidding strategy specifically top target the percentage of top impression share that you set.

Search Absolute Top Impression Share

Search absolute top impression share is the number of impressions you received in position 1 of the SERPs divided by the total number of impressions you were eligible for in position 1.

Search Absolute Top IS (%) = Abs. Top Impressions / Total Eligible Abs. Top Impressions

This metric can help you manually bid to target position 1 in the SERPs. Although much like top impression share, Google has a bidding strategy in which you can set a specific absolute top impressions percentage for Google to optimize your bids to.

Search Lost Impression Share (Rank)

Search lost impressions share (rank) shows how much impression share you’re losing due to poor ad rank. Ad rank is calculated using your bid, quality score, context of the search, ad rank thresholds, and the expected impact of extensions and other ad formats. This metric is also available at the campaign, ad group, product group (for shopping), and keyword level of Google Ads.

A tip when evaluating your impression share lost to rank is to look at a longer period of time and segment your data by day, week, or month to see where you may have either made an improvement, or see when you started losing impression share, due to rank. You can then check the change history during that time and see if you made any changes that may have positively or negatively impacted your impression share.

Search Lost Impression Share (Budget)

Search lost impression share (budget) show how often your ads didn’t show due to budget. Whenever you see the ‘limited by budget’ warning within Google Ads UI this means that campaign is losing impression share due to budget.

Google will give you a recommendation on what the budget of that campaign could be as well as the potential increase in clicks and conversions. This metric is helpful when trying to decide if you can spend more on your current keywords and bids.

If your impression lost due to budget is at 10% and your overall budget is at $10,000 you’d be able to spend another $1,000 ($10,000 x 10% = $1,000).

Auction Insights Report

The auction insights report is a very powerful report within Google Ads. It provides insights into your impression share in comparison to competitors who are also in the same auctions as you.

The auction insights report shows the actual domains of your competitors, which helps see if your competing with your the competitors in your space or if you need to do some more keyword research because you’re competing against businesses that aren’t in your space. You can also segment this data by day to see if competitors are gaining more impression share and respond appropriately to ensure you maintain as much impression share as possible. When segmenting by day you’ll be able to see exactly who is taking impression share from you or who you are taking impression from!


Understanding the components of impression share will help give you insights to see if you’re getting the most out of your current campaigns, ad groups, product groups, and keywords. Whether your rank is low or you can spend more impression share is where you can see specific areas that need improvement.