What Is Google PageSpeed Insights?
Google PageSpeed Insights (PSI) is a free tool from Google that analyses the loading performance of a web page on both mobile and desktop devices. It generates a score from 0 to 100 based on how well the page performs against a set of performance metrics, and it provides a prioritised list of specific recommendations for improvement. The tool is available at pagespeed.web.dev and runs on the same Lighthouse audit engine that powers Chrome DevTools.
The score is broken into four colour-coded bands: 0 to 49 is poor (red), 50 to 89 needs improvement (orange), and 90 to 100 is good (green). Google feeds real-world performance data from Chrome users into the report through the Chrome User Experience Report (CrUX), so the tool shows both lab data from a simulated test and field data from actual users visiting your site.
For South African websites, mobile performance is particularly critical. A large proportion of local web traffic arrives on mobile devices, often over 4G connections that are slower than fixed-line broadband. A page that scores 90 on desktop may still score poorly on mobile if images are not optimised or third-party scripts are blocking render.
Core Web Vitals Explained
PageSpeed Insights reports three Core Web Vitals that Google uses as ranking signals. Largest Contentful Paint (LCP) measures how long it takes for the main content to load and should be under 2.5 seconds. Cumulative Layout Shift (CLS) measures visual stability as the page loads and should be below 0.1. Interaction to Next Paint (INP) measures responsiveness to user input and should be under 200 milliseconds. Failing any of these thresholds means your page experience may be affecting your search rankings.
Improving your PageSpeed score typically involves compressing images and converting them to modern formats such as WebP, deferring non-critical JavaScript, preloading key resources, and using a fast hosting provider or content delivery network (CDN). Each recommendation in the report comes with an estimated time saving so you can prioritise the changes with the greatest impact.
FAQ
What is a good Google PageSpeed Insights score?
Scores of 90 or above are considered good. Scores between 50 and 89 need improvement, and scores below 50 are considered poor. Most competitive South African websites should aim for a mobile score above 70 and a desktop score above 90.
Does PageSpeed score affect Google rankings?
Yes. Google's Core Web Vitals, which are measured by PageSpeed Insights, are ranking signals. A slow page with poor LCP, high CLS, or poor INP scores can rank lower in search results compared to faster competitors, particularly since Google's 2021 Page Experience update.
How do I improve my PageSpeed score?
Key improvements include compressing and converting images to WebP format, eliminating render-blocking JavaScript and CSS, enabling browser caching, using a content delivery network (CDN), and reducing third-party scripts. PageSpeed Insights provides specific recommendations tailored to each page.