Google Pagespeed Insights score is a measurement of the performance of your website and the three core web vitals that are measured in that score do have an impact on your website’s SEO.
Your overall SEO ranking is improved when you create good, useful content that your audience finds relevant.
It is highly improbable (if not impossible!) that your website will get a score of 100/100. Unless your website is text only and has no dynamic elements such as images, videos, and animations, certain features on your site will decrease your score. Even Google’s own products, such as Google Analytics, can decrease a score. You will need to decide whether it’s more important to have a high score or if it’s more important to have a website with a more engaging design and functionality.
Google PageSpeed Insights is meant to be used as a diagnostic tool so that you can assess and apply targeted fixes to the specific areas that the test highlights. Improving these areas as much as you can (within reason) will improve your audience’s experience with your site.
You have no control over third-party scripts that load on your website. If you load a YouTube video for example, the code needed to load that video will impact the score. Even loading Google Analytics will have an impact on your score!
How does it work?
Google PageSpeed Insights is a tool built by Google to measure and to help you improve your site’s performance on mobile and desktop devices. After entering a URL, Google will analyze your site’s performance and provide recommendations on how to improve the site speed and performance.
The tool provides metrics for the three "Core Web Vitals" measured by the tool, including:
Largest Contentful Paint measures how much time it takes to load the largest content area on your site.
First Input Delay measures how much time is needed before someone can interact with your site.
Cumulative Layout Shift measures how much time it takes for your content to completely finish loading.
These three Core Web Vitals focus on user experience and how users interact with your site.
Why is it important?
Your results from Google PageSpeed Insights matter. Though your overall Google PageSpeed score on its own isnot a ranking factor for SEO, your website's SEO ranking is impacted by mobile speed and user experience, two areas that are measured by your Google Pagespeed Insights scores.
This means the score can be a helpful indication of how well your site performs and can help you identify ways to improve your overall site performance.
How should you use it?
While your site loading speed is an indication of your site's performance and is a factor in SEO, the more valuable aspects of the Google Pagespeed Insights results are the specific recommendations.
The Google PageSpeed Insights tool is meant to be used as a diagnostic tool so that you can assess and apply targeted fixes to specific pain points. Not every recommended fix can be used for every website! Your website may have features that will completely stop working if you fix every one of the “issues” that the tool highlights.
Here are some examples of improvements that we’ve made for sites thanks to Google PageSpeed scores. We took:
Dr. Kate White’s site from a 40 to 76
Fred Ebb Foundation’s site from a 76 to 85
Team4Tech’s site from 33 to 87
FoodFinders’s site from 23 to 96
All of these sites achieved these increases by doing the following:
Manually resizing images
Serving images in optimized formats (WebP and AVIF over PNG or JPEG)
Cleaning up unused themes and plugins
Preloading larger images and fonts (so that they are there when the site wants to load them)
Implementing lazy loading (Instead of loading the entire web page in one go, only loading certain sections and delaying the remaining until needed) either through custom code or plugin
Installing and configuring optimization plugins such as WP Rocket, WP Rocket No Cache, Autoptimizer and Imagify
The key is balancing optimizing your site to strive for a higher PageSpeed Score with the user experience of content. For these examples, even though some changes would have given us a higher score, we chosenot to change:
Large hero images used for their visual appeal
Micro-interactions and animations designed to engage the user
Video and photo galleries where specific files were important for video and image quality
In summary, Google Pagespeed results are best used as a guide to help you improve your site's usability and performance.