Site Performance: Understanding PageSpeed Insights

4 min read
Google PageSpeed Insights is a tool that tests your site page's performance for both desktop and mobile. This tool uses Google Lighthouse to give your page an overall score, and provide constructive suggestions for areas of improvement.

Learn more about:

Want to access PageSpeed Insights?
Click here to enter your page's URL and view your performance report.

The difference between PageSpeed Insights and Google Lighthouse

Lighthouse is a full report of your site, taking multiple measures into account. It analyzes performance, SEO, accessibility, and best practices to give you an overall score.
PageSpeed Insights takes measurements from Lighthouse to provide a report exclusively on site performance. 
Page Speed Insights showing a URL's score as 91.

Different scores for mobile and desktop

When you run a page's URL through PageSpeed Insights, you will see separate tabs for desktop and mobile. These reports are split, as the performance and end-user experience can vary depending on the device the site was viewed on. 
Different scores for desktop and mobile are normal. There are a few factors that contribute to mobile results being lower than desktop.
Page speed Insights showing a URL's mobile score of 49.

Understanding reports

When analyzing your PageSpeed Insights score, you can see field data from real visitors, as well as lab data based on simulations run by Google. If you don't have enough data from real site visitors, your score is based on data from the lab simulations. 
Click an option below to learn more about each type of report:

Variations of scores between tests

Scores will often fluctuate between tests, even if they are performed one after the other. This can be caused by a number of factors, including local networks and CPU load. These metric variabilities have different levels of impact (low, medium, and high), and the Insights report may not have sufficient time to mitigate them. 
Variations in scores are generally minimal, and are normal. Scores will also change as a site is updated. 

Understanding Google's suggestions

As well as displaying a score and metrics, the report also provides suggestions to improve your site's performance. These insights are displayed under two sections:
  • Opportunities: This displays suggestions on enhancing your site's performance. Each suggestion also provides an estimate on how much faster the page will load if the suggestion is applied.
  • Diagnostics: This section displays additional information on how a page is adhering to best practices.
As well as implementing suggestions provided by Google, we also recommend following our guidelines for optimizing your site's performance and loading time. Learn More 

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