Help Understanding your results
PERF
Use PERF to inspect the deep audit’s lab performance measurement for a page.
PERF overview
PERF is the Lighthouse Performance score from 0 to 100, measured in a controlled mobile lab run. It appears alongside SSPS+ in the page header when that measurement is available. The metric breakdown is in Performance check.
It is a separate score and does not feed SSPS+. A full-site crawl requests a quota-waived homepage deep audit; manual deep requests for other pages use the monthly allowance. Read the last-deep-audit date to identify the measured version.
What it measures
The card shows LCP for main-content loading, CLS for layout shifts and TBT for blocking during loading. It also shows FCP, Speed Index and TTI. These six rows provide detail alongside the overall PERF score; their values are not all in the same unit.
Each measured row shows a value and a coloured threshold bar. Missing values show a dash and unrun checks show their pending state. Neither is measured zero.
How to read it
The interface colours PERF green at 90–100, amber at 50–89 and red below 50. SSPS and SSPS+ use different display bands. Read the numeric score and the individual measured values when comparing results.
A later standard fetch can clear saved deep measurements if the extracted content changed. Run a deep audit to obtain performance data for the updated page.
What to do when it’s low
- Open Performance check in Page audit and read the affected metrics.
- Share the findings with whoever maintains the page. Open the relevant Technical recommendation for available instructions.
- Apply the fix and run Run deep audit to measure again. Manual deep requests use the monthly page allowance.
What it does not mean
It isn’t what your visitors experience. PERF is a lab measurement — one page, one simulated mobile device, one moment. Real visitors are on different networks and devices, and their experience can be better or worse than this number suggests.
It doesn’t predict whether AI cites you. Speed is measured on its own and nothing more. A page that loads instantly and says nothing useful stays uncited.
Its colours don’t line up with the other two scores. PERF uses Lighthouse’s own bands, which are wider than the ones on SSPS and SSPS+. An amber PERF and an amber SSPS are not the same distance from good, so don’t compare the rings at a glance.
A few points of movement is noise. Lab runs vary. Look for changes of a size that a person could have caused.
It isn’t a Google ranking signal readout. Core Web Vitals matter to search, but this is a lab summary in Supasaito, not a report on how Google is treating your site.