Site Performance: Understanding PageSpeed Insights

Google PageSpeed Insights is a tool that tests your site page's performance for both desktop and mobile. This tool uses the Chrome User Experience (CrUX) report to analyze real visitor performance and Google Lighthouse to give your page a performance score.

When reviewing your PageSpeed Insights score, you can view different types of data depending on your site and needs. Your site's pages have separate Mobile and Desktop reports because the experience of your visitors may differ based on the device they use to view the site.

Google PageSpeed Insights has two distinct sections, each serving a unique purpose:

The Core Web Vitals Assessment enables you to view the average metrics for the past 28-day period. Any modifications to your site will gradually influence the metrics each day until the full impact can be measured within 28 days. 

Field data offers the most accurate measure of your site's performance and pinpoints performance improvements you can take on your site. The Discover what your real users are experiencing section presents performance metrics gathered from actual visitors to your stie. 

The Core Web Vitals Assessment is released on a monthly basis, so improvements can take time to appear within the PageSpeed Insights. The field data is gathered from every Chrome session by visitors who have not opted out of reporting to Google.

The results of your Core Web Vitals Assessment, gathered from the latest 28-day collection period, can vary based on the devices used and network connection. 

Core Web Vitals are an important indication of your site's performance, and one of the many measurements used to determine your site's SEO ranking. 

The performance SEO boost is applied to mobile and desktop pages separately. Each mobile page, and each desktop page can receive up to three boosts, one for each Core Web Vital:

For instance, a mobile page might get a partial SEO boost for LCP and INP, but a full boost for CLS.

While the desktop version of the same page gets a full SEO boost for each metric: LCP, INP and CLS. 

Your Core Web Vitals Assessment will show as ‘Failed’ unless you receive a ‘Good’ score for all three Core Web Vital metrics. This does not mean the page hasn’t received a boost, as each metric contributes a boost independently.

Google Search always seeks to show the most relevant content, even if the page experience is sub-par. For most queries, there is a lot of helpful content available, so having a great page experience can contribute to success in search ranking.

Content remains the most important factor in maintaining your SEO score. We recommend optimizing your site's content, as well as updating your page's meta tags. Learn more SEO best practices.

To generate your performance score, Google uses Lighthouse, which is an open-source, automated tool for improving the quality of your web pages. Every time a page is analyzed in PageSpeed Insights, Google estimates the score based on simulated environments:

Google Lighthouse, the tool that calculates the performance score, simulates mobile loading with the conditions of a mid-tier device (Moto G4) on a slow network (4G). For desktop, it simulates an emulated-desktop computer with a wired connection.  

The different scores on mobile and desktop are due to the simulated environments' varying processing power. 

PageSpeed also runs in a Google data center that can vary based on network conditions. You can find out where the test was done by checking the location in the Lighthouse Report's environment block.

Mobile sites often have slower performance compared to desktop sites due to factors like larger images, animations, or third-party scripts. To improve your mobile site’s speed, use lightweight image formats like WebP or AVIF and avoid animations in above-the-fold content. Limiting the use of custom fonts and sticking to standard fonts can also enhance performance. Simplify your mobile layout by hiding unnecessary elements using the Mobile Editor. These steps can help ensure your site offers a smooth and optimized experience for mobile users.

A homepage with too many elements can negatively affect loading speed. To make your homepage load faster, try reducing the number of images and videos, or move non-essential sections to separate pages. Creating a simplified homepage version can also make a big difference in performance. Enabling caching further improves loading speed for repeat visits. Simplifying your homepage not only provides a better user experience but also helps guide visitors through a clearer and more focused user journey.

Largest Contentful Paint (LCP) measures the time it takes for the largest visible element, such as a hero image or header text, to load in the user's viewport. To improve your LCP score, you can optimize the largest element by reducing the size of hero images or system fonts for large text. Additionally, placing heavy content, such as videos or animations, below the fold and implementing lazy loading for non-critical images can significantly enhance the speed and efficiency of your site.

Blocking time refers to delays caused by JavaScript execution or third-party scripts, which can make your site less responsive. Minimizing or removing unnecessary third-party apps or scripts is one way to reduce blocking time. Instead of external code, use Wix's built-in tools whenever possible. For any non-critical scripts, you can add the defer attribute in the Custom Code section to ensure other site assets load first. By reducing blocking time, you can improve your site's responsiveness and overall user experience.

Site speed can sometimes fluctuate even after optimization. These fluctuations are often caused by factors like server response time, visitor location, or cached content. To maintain consistent performance, use a Content Delivery Network (CDN) to serve content globally and regularly check your site's speed using Wix's Site Speed dashboard. Additionally, review third-party apps or scripts that might be causing delays. Speed metrics may take up to three weeks to reflect recent updates, so it’s important to stay patient while monitoring the effects of your optimizations.

Click below for answers to common questions about PageSpeed Insights reports.