Definition
PageSpeed Insights is Google's free tool that reports a page's real-user Core Web Vitals and runs a Lighthouse lab test with suggestions for improvement.
PageSpeed Insights explained
Enter a URL into PageSpeed Insights and it shows two kinds of results. At the top is field data from the Chrome UX Report, showing how real users experienced the page or the whole site, with a pass or fail assessment for Core Web Vitals. Below is a Lighthouse lab test with a performance score and specific diagnostics, such as render-blocking resources, oversized images and unused JavaScript.
The two often disagree, and that is expected. The lab test is a single simulated load on a mid-range mobile device with throttled network conditions. Field data reflects many real visits over time. When they differ, trust field data for how users experience the page, and use lab diagnostics to find causes.
Avoid chasing a perfect lab score for its own sake. A score in the green is pleasant, but what matters is passing Core Web Vitals in the field and giving visitors fast pages.
Example
You run your landing page through PageSpeed Insights before a campaign. The field data fails LCP on mobile, and the diagnostics point to an uncompressed hero image and render-blocking fonts. Fixing both before launch means paid clicks land on a fast page.
Why it matters
It is the quickest free way to see whether a page passes Core Web Vitals for real users and what is slowing it down.
Related service
Page Speed Optimization
We fix LCP, INP and CLS issues so pages load fast and respond quickly for real users.
Page speed and Core Web Vitals optimizationPublished by Vidern, founded and led by Malhar Shah. Updated .
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Related terms
- CrUX (Chrome UX Report)CrUX (the Chrome UX Report) is Google's public dataset of how real Chrome users experience websites, including their Core Web Vitals.
- Core Web VitalsCore Web Vitals are three Google metrics for real-user experience: loading (LCP), responsiveness (INP) and visual stability (CLS).
- Render-blocking resourcesRender-blocking resources are CSS and JavaScript files the browser must download and process before it can show anything on the page.
- LCP (Largest Contentful Paint)LCP (Largest Contentful Paint) measures how long the largest image, video or text block in view takes to render; 2.5 seconds or less is good.