Impression share is the number of impressions your ads received divided by the number they were estimated to be eligible for, given your targeting, approval status and quality. Google Ads and Microsoft Advertising both report it. Paired with the “lost” metrics, it tells you whether budget or Ad Rank is holding a campaign back.
The family of metrics
- Search impression share: impressions received divided by eligible impressions.
- Search lost IS (budget): share missed because the budget ran out.
- Search lost IS (rank): share missed because Ad Rank was too low.
- Search top IS and absolute top IS: how often you showed above the organic results, and in the first position.
- Exact match IS: impression share for searches that exactly match your keywords.
How to act on it
If most lost share is due to budget and the campaign converts profitably, more budget will probably buy more conversions. If most is due to rank, raising the budget does little: you need better quality or higher bids.
For brand campaigns, impression share is a defensive metric. A low number means competitors or affiliates may be taking clicks on your own name.
Caveats
Eligible impressions are estimates, and the figures are rounded, with very high or low values often reported as above or below a threshold. Use impression share to spot direction and constraints rather than as a precise count.
Example
Budget or rank?
Hypothetical company Pebblethorn’s category campaign shows modest impression share, with most of the loss attributed to rank. The team pauses its plan to double the budget and instead rewrites ads and builds a matching landing page, then rechecks lost IS (rank) a few weeks later.
Common mistakes
Aiming for 100% everywhere
Full impression share on low-intent keywords can cost a lot for little return. Prioritize share on terms that convert.
Questions
Reporting for Performance Max is more limited than for standard search campaigns and has been changing. Check current Google Ads documentation for which metrics are exposed.
