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What is Google PageSpeed?

by Iwan Price-Evans on Performance • March 1, 2022

Google PageSpeed Insights (PSI) is a web page performance reporting tool that analyzes pages on both mobile and desktop devices. You can leverage PageSpeed Insights to optimize a site for both the search engines as well as a better user experience. 

PageSpeed measures the performance of all aspects a user would interact with on a web page and takes this into account when it comes to where the page will rank in its search index.

You can see how your pages are performing when it comes to speed, engagement, interactivity. By simply entering a URL PageSpeed will analyze the web page and generate a performance report. 

PageSpeed has some very helpful tools such as the ability to generate a preview of how Google saw the page load when it indexed it. From this, you can identify any lag in page loading.

What is Google PageSpeed made up of?

Google Search Console is integrated with PageSpeed Insights and this combination of tools gives you great insight into your web page performance. PageSpeed uses the open-source Lighthouse tool to analyze URLs and generate its reports.

Some of the key metrics PageSpeed identifies are:

  • How fast does the website load?
  • How fast does the main content get into the view of the user?
  • How long does it take for a user to engage with your page?
  • Is the page stable or do things move around as it's loading? 

Specifically, PageSpeed uses real-world user experience metrics such as:

  • First Contentful Paint (FCP)
  • First Input Delay (FID)
  • Largest Contentful Paint (LCP)
  • Cumulative Layout Shift (CLS)

PageSpeed rates each page's performance as Good, Needs Improvement, or Poor. It scores a page's performance out of 100. Good is 90 or above; 50 to 90 is considered Needs Improvement; below 50 is considered Poor. It will grade a page and identify if it is failing and report why it is failing.

The data collected about a page's performance are:

  • Field data. This is a historical report about a URL and how it’s performed over time. Field data allows you to capture useful information on real-world user experience.
  • Lab data. This will tell you exactly how your page has been performing. It allows you to debug performance issues on your pages. It's important to note that Lab data collects data in a controlled environment and so it may not capture real-world performance issues.

What are Core Web Vitals?

Google uses a common set of performance metrics that it considers are critical to all user experiences. These are three of the PageSpeed metrics which are FID, LCP, and CLS. 

Why is Google PageSpeed important?

Google looks at PageSpeed metrics very closely and they play a big role when it comes to where Google ranks your site in its search results.

How to improve Google page speed?

You can check your page speed and user experience performance by analyzing a URL via the Google search console. The generated report can appear complex and so it’s key to be able to interpret this information. 

You can look at your page speed on mobile and desktop. Google ranks sites in its index based on mobile-first performance so when analyzing PageSpeed reports focus on the mobile data first then the desktop data. 

The PageSpeed report separates its page audit into three sections:

  • Opportunities that allow you to identify ways to help you load your page faster. This section will list suggestions for improvements and indicate how much faster the page will load if you implement that change.
  • Diagnostics gives you a deeper look at how you can improve the performance of your website or application. This section will tell you how well your pages are built in relation to web development best practices.
  • Passed Audits lists the passed audits for the analyzed page.

Use Google's online developer documentation to learn more about how to use PageSpeed Insights.