Core update
A core update is a broad change Google makes to its search ranking systems, several times a year.
A core update is a broad change Google makes to the systems that rank its search results. Google says it makes them several times a year, announces them on its Search Status Dashboard, and that they don't target particular sites or pages.
After a core update, some sites rise in Google's results and others fall. For AI search, that matters too: Google's AI Overviews and AI Mode are part of Google Search, so when the pages Google ranks shift, the pages its AI answers draw on can shift with them.
What Google advises
Google's own advice is calm. Most sites don't need to worry, and many won't notice an update happened. Wait at least a full week after an update finishes before you analyse your numbers. Avoid changing content that's already doing well. If you've seen a large, lasting drop, review your site against Google's guidance on helpful, people-first content, and focus on changes that serve your readers over quick fixes.
Reading an update in AI answers
An update can show up in AI answers in two ways. The AI answers in Google may cite different pages, because Google's ranking changed. And other platforms that use search results may shift too, if the sites they read rise or fall.
For example, Fernhill's visibility in AI Overviews drops from 30% to 18% in the two weeks after an update finishes. Its numbers on ChatGPT and Perplexity barely move. The answers in Google now cite a different set of review sites, and two of them don't mention Fernhill. Those two sites are where to look.
In AnswerOrbit
Before and after a date in Recommendations shows your numbers before and after a date you pick, platform by platform. Pick the day the update finished. How we count explains when we mark a change as bigger than a normal week's ups and downs.