PageSpeed Insights is an online tool by Google for measuring website performance. In addition to overall performance, it also evaluates best practices, accessibility, and SEO.

If you want to check your website’s health, speed, and performance, visit PageSpeed Insights here, put your website URL there in the field, and click on the Analyze button.

Accessibility, Best Practices, and SEO should always have a score of 100. And the performance score should always be above 95.

Under Metrics, all the metrics, First Contentful Paint, Largest Contentful Paint, Total Blocking Time, Cumulative Layout Shift, and Speed Index will have a green circle before them, indicating it’s a good result.

No yellow squares (needs improvement), No red triangles (poor).

The following image shows an example of a bad result.

Google PageSpeed Insights bad performance metrics: First Contentful Paint – 2.6s (needs improvement), Largest Contentful Paint – 2.9s (needs improvement), Total Blocking Time – 240ms (needs improvement), Cumulative Layout Shift – 0.313 (poor), and Speed Index – 9.4s (poor).

And this image shows an example of a good result.

Google PageSpeed Insights good performance metrics: First Contentful Paint – 0.8s (good), Largest Contentful Paint – 2.1s (good), Total Blocking Time – 0ms (good), Cumulative Layout Shift – 0 (good), and Speed Index – 1.0 s (good).

And all these results should be for Mobile, not Desktop. I mean we should focus on how our website is performing on mobile devices first. If the mobile score is good, the desktop score is good as well, automatically. By default, PageSpeed Insights shows us the mobile result, which is good. However, you can toggle between Mobile and Desktop there.

PageSpeed Insights uses a throttled Slow 4G connection to simulate performance on mobile networks.