Google PageSpeed grade does not improve

WP Rocket helps to improve the Google PageSpeed grade and Core Web Vitals (CWV) metrics of a website.

In this article, you can find the general guidelines to improve all these results, how you can use WP Rocket optimizations to improve your results, learn more about the insights, what to check if the grade does not improve, and find other useful information.

General guidelines

In general terms, you can achieve the best results when:

• You have configured the WP Rocket settings.
• There is no excessive use of exclusions.
• The site has a good baseline performance: hosting, plugins, content, etc.

How to improve the Core Web Vitals

Google's Core Web Vitals (CWV) are the key metrics of a website performance, they determine the PageSpeed grade, and they can be improved by following the general guidelines.

If you want to learn more about each of the CWV, or you need to improve the results even more, please refer to the following specific guides:

• Cumulative Layout Shift
• Interaction to Next Paint
• Largest Contentful Paint

How to improve the PageSpeed grade

Using the general guidelines should be enough to improve the PageSpeed grade. Here's an overview of the WP Rocket features, and the PageSpeed insights.

Key WP Rocket features

All WP Rocket features will make your website faster, but the following are the most impactful features that help improve the PageSpeed score and the Core Web Vitals:

• Page Cache, including Mobile Cache - It makes the page loading much faster by removing the processing of PHP and MySQL. 
• Remove Unused CSS - It reduces the overall page size by removing the unused CSS rules from your pages. 
• Delay JavaScript execution - It improves the rendering of the page by delaying the execution of JavaScript until user interaction.
• Load JavaScript deferred - It helps to render the page faster by deferring the render-blocking JavaScript.
• LazyLoad - It helps to reduce the page size by deferring the loading of images that are outside the viewport.
• Optimize critical images - It optimizes the above-the-fold images of a page, prioritizing them and excluding them from the LazyLoad.
• Preload fonts - It detects and prioritizes the fonts used in text above-the-fold, allowing them to be displayed faster.

PageSpeed insights

Alternatively, if you need to focus on the PageSpeed insights rather than the WP Rocket features, please refer to these specific articles:

• Layout shift culprits
• Document request latency
• Optimize DOM size
• Duplicated JavaScript
• Font display
• Improve image delivery
• INP breakdown
• LCP request discovery
• LCP breakdown
• Legacy JavaScript
• Modern HTTP
• Network dependency tree
• Render blocking requests
• 3rd parties
• Use efficient cache lifetimes
• Optimize viewport for mobile

Insights are still present

If you followed the general guidelines, and the insights are still present in the PageSpeed report, please note the following:

1. The insights should have a much lower impact than before:
   • The icons can change from red triangles to yellow squares.
   • The amount of potentials savings (KB of data) was reduced.
2. Reduce the usage of exclusions used across the optimizations. It's recommended to use exclusions only for major issues.
3. Make sure that WP Rocket is caching and optimizing your site.

How to optimize further

There will likely be some remaining recommendations, which cannot be improved with WP Rocket. We’ve covered the most common ones in the list below:

• Improve image delivery
• Avoid enormous network payloads
• Avoid excessive DOM size
• Reduce JavaScript Execution time
• Minimize main-thread work
• Remove Unused JavaScript
• Reduce the impact of 3rd party code

Why is the mobile score worse than desktop

Please see our guide: How to improve your mobile PageSpeed score.

How long does it take to see the improvements

Some WP Rocket's speed improvements take place immediately. However, WP Rocket also has a few asynchronous optimizations, which are key to the performance of a site.

Please make sure the asynchronous optimizations are applied to your site before running the PageSpeed test.

My score isn’t high enough, can you optimize my site for me?

We offer the RocketCare service, where our expert team will handle setup and optimization of WP Rocket on your website, so you won't have to worry about anything.

If you're looking for a service not covered by RocketCare, and beyond our Support scope, then in that case, you may consider Codeable.

Core Web Vitals Assessment: Failed

WP Rocket's impact on the Core Web Vitals Assessment is limited by multiple external factors, such as old devices, slow networks, or poor availability of third party services. 

You can read more information in the Core Web Vitals Assessment article.

GTmetrix grade does not improve

GTmetrix report is powered by Lighthouse, therefore, in most cases, addressing the recommendations in the PageSpeed report as explained above will improve GTmetrix results too.

Accessibility, Best Practices and SEO sections

WP Rocket's optimizations are aimed to address only audits from the Performance section of the PageSpeed report.

Audits and scores in the Accessibility, Best Practices and SEO sections are outside WP Rocket's scope, and should be addressed as instructed in Lighthouse official documentation:

• Lighthouse accessibility audits
• Lighthouse best practices audits
• Lighthouse SEO audits

WP Rocket errors on Mobile Friendly audits

In some cases, WP Rocket could trigger these Mobile Friendly audits in the SEO section of the PageSpeed report:

• Document doesn't use legible font sizes
• Tap targets are not sized appropriately

Firstly, to confirm WP Rocket is involved, you should check the test results with the  ?nowprocket query string added to the affected URL. This will bypass WP Rocket's optimizations.

You can conclude WP Rocket is causing the problems when they  don't appear in the ?nowprocket report. In those cases, you'd need to find which is the problematic feature as per this basic troubleshooting guide.