Google has published an official help page for negative keyword impact prediction in Performance Max campaigns.
The feature itself is not new, it was first spotted in April 2026, but until now Google had not officially announced or documented it anywhere. This help page is the first official confirmation of how the feature works.
According to the help page, advertisers can preview the impact of up to 10 negative keywords at a time through the Search Keywords section. The predicted impact is shown as a percentage change in conversions or conversion value, depending on the campaign’s bid strategy.
The documentation also confirms the prediction covers Search and Shopping inventory, works for existing negative keywords too, and is currently limited to Performance Max campaigns, though it may roll out to other campaign types in the future.
Here’s the official help page found by Hana Kobzová: Estimate the impact of adding negative keywords to your Performance Max campaign.