Google PageSpeed grade does not improve

WP Rocket improves the Google PageSpeed grade and Core Web Vitals (CWV) of a website.

In this article, you'll learn what to do when the PageSpeed grade does not improve. You’ll find the general guidelines and tips, information about audits, as well as limitations and other useful information.

General guidelines

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

• You have activated the WP Rocket optimizations.
• 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 and CWV. 

To provide more information, here's an overview of how the main WP Rocket features can help, and which are the key PageSpeed insights to focus on.

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, you could focus on the following PageSpeed Insights metrics that can be optimized using WP Rocket:

• Layout shift culprits
• Document request latency
• Font display
• INP breakdown
• LCP request discovery
• LCP breakdown
• Network dependency tree
• Render blocking requests
• Use efficient cache lifetimes

Insights are still present

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

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 in the optimizations. Use exclusions only for critical issues.
3. Make sure that WP Rocket is caching and optimizing your site.
4. Check for insights that WP Rocket can't resolve.

Insights that WP Rocket can't fix

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
• Optimize DOM size
• Duplicated JavaScript
• Legacy JavaScript
• Modern HTTP
• 3rd parties
• Forced reflow
• Optimize viewport for mobile

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