Impression Share
Also known as: IS, search impression share
Impression share is the percentage of impressions your ads received divided by the total impressions they were eligible for. Google also reports lost impression share due to budget and due to rank, showing why you missed the rest. It reveals how much of your available market you are actually capturing.
Key Takeaways
- Impression share is the percentage of impressions your ads received divided by the total impressions they were eligible for.
- Google reports lost impression share due to budget and due to rank, showing why you missed the remaining eligible impressions.
- It reveals how much of your available market a campaign is actually capturing.
- Chasing 100 percent impression share is usually inefficient, since the last slices come at a steep cost.
- Low impression share lost to budget suggests raising spend; lost to rank suggests improving Quality Score or bids.
How It Works
Impression share is calculated by dividing the impressions your ads actually earned by the total impressions they were eligible to earn based on targeting, settings, and approval status. The result tells you what slice of available demand you captured.
Google splits the gap into two diagnostics. Impression share lost to budget means your daily budget ran out before all eligible auctions. Impression share lost to rank means your ad was not competitive enough to show, which ties directly to Ad Rank, your bid, and your Quality Score.
Reading these together guides action. If you lose share to budget, more spend captures more demand. If you lose share to rank, better ads, landing pages, or bids help more than budget alone. Pushing for total dominance rarely pays off, because the final impressions often push Cost Per Acquisition past a profitable level.
Why It Matters
Impression share shows your headroom for growth. If you are winning only a fraction of eligible impressions, you know whether budget or ad rank is holding you back and where to invest to capture more demand.
Example
A local dentist runs search ads and sees 45 percent impression share, with 30 percent lost to budget and 25 percent lost to rank. The budget loss signals real demand going uncaptured, so they raise the daily budget. For the rank loss, they improve ad copy and landing page relevance to lift Quality Score, capturing more auctions without simply overbidding.
Common Mistake
Chasing 100 percent impression share as a goal. Dominating every auction is usually expensive and inefficient. The last slices of impression share often come at a steep cost per acquisition.
Frequently Asked Questions
How is impression share calculated?
Divide the impressions your ads received by the total impressions they were eligible to receive, based on your targeting and settings. Multiply by 100 for a percentage. Google estimates the eligible total, so treat the figure as a close approximation.
What is a good impression share?
There is no universal target. A healthy figure depends on your goals, budget, and margins. Many advertisers aim for strong share on high-intent, branded, or core terms while accepting lower share on broad or exploratory keywords.
Should I aim for 100 percent impression share?
Usually no. Winning every auction is expensive, and the last impressions tend to convert least efficiently, driving up cost per acquisition. Full dominance can make sense for brand terms, but for most keywords it wastes budget.
What is the difference between budget and rank loss?
Impression share lost to budget means you ran out of money before all eligible auctions. Lost to rank means your ad was not competitive enough to show. Budget loss calls for more spend; rank loss calls for better ads or bids.