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Improving your Site Speed Score

Jetpack offers several tools to improve your site’s speed, including Site Accelerator and Jetpack Boost. However, in some cases, you may want to make additional improvements. This guide offers some suggestions on how to improve your site’s speed and performance.

Note: Optimizing your site’s speed and performance isn’t something we can assist with per our Scope of Support. The suggestions here are provided as-is. 

Measuring your Site Speed

In Jetpack Boost, we provide a numeric score and letter grade that indicates your site speed score as measured by Google.

An example screenshot showing this:

Screenshot showing Site Speed Score in Jetpack Boost

In some cases, you may find that you want to continue to optimize the speed of your site or that Jetpack Boost doesn’t make the improvement you are looking for. What follows are some additional suggestions.

While the numbers in Jetpack Boost give you some guidance, you can get more information using Google’s PageSpeed Insights tool. This is the same tool used by Jetpack Boost to measure your site, but by running it directly on your site, you get more insight into why your site has been given a specific score. Additionally, Google provides recommendations for how to address the issues it encounters.

Screenshot showing Google PageSpeed Insights report
Screenshot showing Google PageSpeed Insights

Common Improvements

The following are some common steps that you can take to improve your site’s speed. Depending on the site’s goal, not all recommendations suit all situations. As you work through the recommendations, you can test periodically to see if the site speed improves. 

Additionally, as you update your site and add plugins and content, you may find that your site speed changes. Over time, strategies that worked in the past may not have the same effect they once did. We recommend testing your site’s speed regularly and making adjustments as needed.

Optimize CSS Loading

Your website’s appearance is controlled by CSS, which tells the web browser how to display your site’s content. Because of the amount of content on modern websites, CSS files tend to be quite large. Additionally, plugins may add their own CSS. This means that a large amount of information has to be parsed before your content is displayed. 

This can be sped up by optimizing your CSS loading so that the code needed to display the immediately visible content is given to the browser first. This helps speed up the initial page load. This is referred to as Critical CSS. While this is difficult to do manually, Jetpack Boost does this for you.

Jetpack Boost also offers a paid upgrade that generates Critical CSS automatically each time your site changes.

Enable Jetpack Site Accelerator

Jetpack Site Accelerator is a content delivery network (CDN) that can help speed up your site by serving optimized images and cached static assets (CSS and JavaScript) from high-speed and dedicated data centers. It will automatically resize images and serve them in the best format for your site, which can reduce your site’s load time. Additionally, it will load certain core WordPress files from these data centers. 

Lazy Load Images

Lazy Loading makes pages load much faster by only loading visible images while waiting to load off-screen images as you scroll down. This feature can improve site performance and is especially great for users in low-bandwidth or expensive-bandwidth environments, such as users on mobile devices. You can enable Lazy Loading in Jetpack or Jetpack Boost.

Optimize Images

Images can be a major source of slow site speeds. Large and unoptimized images are a frequent cause of this.

In addition to techniques mentioned elsewhere in this guide (using a CDN), you might consider optimizing images before adding them to your site. For starters, it helps to choose the proper image format for your situation. For example, a PNG is good if you need transparency, but if you are uploading a photo, it isn’t a good choice. Google has an excellent guide for choosing the right image format.

You should also size images appropriately for your content area. For example, if your theme serves images at a maximum width of 1,000 pixels wide, you can resize your images to be 1,000 pixels wide before uploading them. Additionally, you can optimize your images using your image editing program or a tool like TinyPNG or JPEGmini. There are also many third-party plugins for image optimization.

Jetpack Boost includes an Image Performance Guide that can help identify images that may need additional optimization.

Add a Caching Plugin

Adding a caching plugin to your WordPress site can help increase your site speed. Typically, when a page is accessed on a WordPress site, the requested page is compiled on the server when someone visits it. This requires multiple calls to your site’s database. This is generally fine, but if many requests are being made simultaneously, it may slow down your site.

A caching plugin helps, as it will save a page once requested. The next time that page is requested, the plugin WordPress will use the previously compiled page rather than making a new request. This reduces the load on your server by eliminating database requests. 

We recommend the WP Super Cache plugin, which is made by our parent company, Automattic, and works with Jetpack. You can read more about configuring it on the WP Super Cache wiki.

Note: If your site is hosted on WordPress.com, caching is already built-in, and you don’t need a separate plugin.

Reduce Unnecessary JavaScript

When you test your site with Google’s PageSpeed Insights, you may see mention of reducing JavaScript. Some common suggestions are “Reduce JavaScript execution time” and “Reduce unused JavaScript”. To help with this, you can try turning on the “Defer Non-Essential JavaScript” setting in Jetpack Boost.

If you are still having this issue, you may want to remove JavaScript that you aren’t using. For example, if your site has Google Analytics and you are never using the Analytics data, it may not make sense to collect it, and removing the script from your page may increase your site speed. 

Unused third-party scripts can also increase your site’s load time. It is worth checking to see if there are unused scripts that can be removed. If you use Google Tag Manager, you should ensure you need all the scripts added to your site.

Reduce Unused Plugins

The more plugins you have installed on your site, the more resources your server needs to respond to requests. You can potentially improve your site speed score by removing plugins that you are no longer using. Depending on the plugins installed, this will remove unused JavaScript and CSS assets that may be loading on your site.

Consider a Theme Change

Your site’s theme may be contributing to slow load times. The quality of WordPress themes varies widely, and some are more performant than others. It can be worth testing your page speed with different themes. You might find that your theme is the bottleneck, so changing the theme would be an excellent next step.

Add a Content Delivery Network (CDN)

A Content Delivery Network (CDN) can help increase your site’s speed by caching requests and serving pages from data centers close to your visitors. The shorter distance data has to travel, the faster the page load time. A popular solution with a generous free plan is Cloudflare. You can read about how to configure it with Jetpack here. Cloudflare also helps to block malicious requests, which can further reduce server load.

If your site hosts video content, you might want to consider loading this content from a cloud-based server. Jetpack VideoPress can automatically load optimized videos from data centers close to your site’s visitors, enhancing your site’s speed.

Offload Resource Intensive Tasks to Cloud Servers


At the core of any WordPress installation is a database. Each time a page loads, WordPress queries the database and then displays the page. All of your site’s content is in this database, and depending on the plugins and functionality used on your site, large numbers of queries can slow down your site. Some tasks in WordPress, such as search and plugins that generate related content, are particularly intensive. Jetpack’s Search and Related Posts allow you to offload this work to WordPress.com’s servers.

Reduce Server Response Time

The actual performance of your web server can also affect site speed. If this is the case, you may see an indicator in Google PageSpeed identifying an issue with the Time to First Byte (TTFB) on your web server. If Google PageSpeed indicates that your server is slow, you will want to reach out to your hosting provider. They may be able to offer additional advice or upgrade your account.

If they cannot assist, you may wish to move to a different and more performant host, such as WordPress.com. Business plans and above allow you to install plugins.

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