Impression Share shows how much of its visibility opportunity an ad captures on Google Ads. In search campaigns in particular, it answers the question: “Out of all the opportunities where my ad was eligible to show, how many of them did it actually show for?”
This metric doesn’t just show how many impressions were received — it also shows how many impression opportunities were missed.
Google Ads’ explanation of impression share recommends evaluating impression share loss separately by budget and by rank. WordStream’s benchmark data and the eBay paid search case study are a reminder that visibility alone doesn’t create value — what matters is which query you’re visible for.
What Is Impression Share?
Visibility opportunity
Impression Share shows how much of the estimated impressions an ad could receive it actually received. It’s a way of quantifying how visible the ad was relative to its full opportunity.
For example, if an ad showed for 400 of 1,000 eligible impression opportunities for a given campaign or keyword, its Impression Share would be roughly 40%.
What Is Search Impression Share?
Search Impression Share refers to impression share within search network campaigns. It shows how much of the ad’s eligible opportunity was captured during moments when users were actually searching.
This metric matters especially for high-intent keywords, because whether the ad is visible while a user is actively searching for a solution, service, or product can directly affect the campaign’s outcome.
What Is Lost IS (Budget)?
Lost IS (Budget) refers to the impression share missed due to insufficient budget. If the campaign budget hits its limit during the day, the ad can miss the chance to appear for eligible searches.
If this value is high, campaign budget, keyword priorities, or bid strategy may need a second look. That said, increasing the budget isn’t always the only fix. You first need to decide which queries are actually valuable; for example, if Lost IS (Budget) is 40%, whether that loss is concentrated in the most valuable 20% of queries or spread evenly across all queries determines where the budget should actually go.
What Is Lost IS (Rank)?
Loss due to rank
Lost IS (Rank) shows the impression share missed because of ad rank. Rank can be affected by many factors: bid, ad relevance, landing page experience, and quality signals, among others.
If this value is high, it’s worth reviewing ad copy, keyword match, and page experience rather than simply raising the bid. To understand the quality side in more depth, see What Is Quality Score?
What Are Top Impression Share and Absolute Top Impression Share?
Top Impression Share describes how often an ad appears in the top positions of search results. Absolute Top Impression Share describes how often it appears in the very top position.
These metrics clarify visibility particularly in highly competitive search campaigns. But chasing the absolute top position isn’t always necessary — cost and conversion need to be weighed together.
What Should You Do If Impression Share Is Low?
If Impression Share is low, the first step is understanding why. Is the issue budget, rank, targeting, or keyword coverage?
If the loss comes from budget, campaign priorities can be adjusted. If it comes from rank, ad relevance, landing page, and bid level should be examined. In every case, the goal isn’t simply to be seen more — it’s to be seen in the right searches.
Impression Share vs. CPM/CPC
Impression Share reflects visibility opportunity, while CPM and CPC reflect cost. CPM is cost per thousand impressions; CPC is cost per click.
For a closer look at these differences, see What Are CPM, CPC, and CPA?
How Should Impression Share Be Interpreted in B2B Campaigns?
Visibility for valuable searches
In B2B service campaigns, low Impression Share on valuable keywords can mean lost opportunity. Particularly for specific service searches close to purchase intent, insufficient visibility can translate directly into lost demand.
That said, chasing 100% Impression Share on every keyword isn’t necessary. For generic, low-intent, or expensive keywords, more limited visibility can actually be healthier. What matters is directing budget toward searches with genuine demand potential.
A Common Mistake
Treating Impression Share as a standalone success metric on its own is a common mistake. A high impression share doesn’t necessarily mean the campaign is producing good results.
An ad can be highly visible, but if clicks, conversions, or lead quality are low, that visibility isn’t translating into business results.
Summary
Impression Share measures the visibility opportunity in Google Ads campaigns. The real question is: which is higher, Lost IS (Budget) or Lost IS (Rank)? Increasing budget without knowing this distinction usually doesn’t help.
For the broader metric framework, see Google Ads Metrics Guide.