Your PageSpeed Insights score may have gone up, and you may not have changed a thing. PageSpeed Insights is now using Lighthouse 13.6.0, which was released on October 27, 2026, and the new version changes how it simulates how long a page takes to load. Search Engine Journal reported on November 2, 2026 that the update improves the simulated First Contentful Paint and Largest Contentful Paint, and that scores will generally be higher as a result. A page may receive a different PageSpeed Insights score without anything on it changing, because the test itself changed.
By default, Lighthouse loads a page at full speed and then estimates how it would load on a slower connection. The simulation behind those estimates is called Lantern, and the release notes for version 13.6.0 list several changes to it aimed at improving its accuracy. The first change is about render-blocking requests. Lighthouse 13.5 used each request's fetch priority to decide whether or not it blocked rendering. In 13.6, Lantern uses Chrome's own render-blocking label for each request, falling back to priority only when that label is missing.
The second change applies when the Largest Contentful Paint element is text that appears in the same frame as the page's first content. Lantern now estimates that LCP from the same requests and page tasks it uses for First Contentful Paint, instead of from a set that can include every request made before LCP. The result is a tighter, more accurate estimate. Chrome's Web Performance Developer Advocate, Barry Pollard, has stated on Bluesky that the updated PageSpeed Insights is now available, and that the improved simulation will be more accurate than before and generally result in higher scores.
The scores that change are lab scores, and the distinction matters. The performance score in PageSpeed Insights is based on data generated by Lighthouse in a controlled, simulated environment. The field data shown in the same report represents real visits to the website within the last 28 days, as reported by the Chrome User Experience Report. A Lighthouse update changes the lab measurement. It does not retroactively change how real visitors' devices, networks, and browsers performed.
That is why the right response to a changed score is to check the field data before celebrating or worrying. If the lab score rose but the field data is unchanged, the site did not get faster. The ruler got better. If the field data also improved, the change is real. Google ranks on real-visitor data, not on lab scores, so the field data is the number that affects visibility, and the lab data is the diagnostic tool that helps you fix it.
Lighthouse 13.6 also updates the Agentic Resource Discovery audit from version 13.5 to version 0.91, continuing Google's work on making sites discoverable by AI agents as well as by people. The release notes say the team expects 13.6 to ship in the DevTools of Chrome 159, which was in Chrome's desktop developer channel and Canary at the time of the report, with Chrome 159 listed for stable release on December 8. An open issue on Lighthouse's GitHub is also looking into cases where the simulated LCP runs far above measured LCP, using large JavaScript and single-page application sites as examples, so JavaScript-heavy sites may see the largest score movements.
For site owners, the practical steps are simple. Re-run PageSpeed Insights on your most important pages and note the new scores, but record which Lighthouse version produced them before comparing with older reports, because scores from before and after the update were not measured with the same simulation. Pay attention to the LCP element the report names, since that is the exact thing that counted as largest, and check whether it is what you expected. And keep improving the real experience, because a better simulation measures the same site more accurately. It does not make the site faster.
Sources: Search Engine Journal, November 2, 2026.
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