How to Successfully Improve WordPress Core Web Vitals

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People use WordPress for various purposes, such as to build an eCommerce website or to improve their online presence. Whatever the website type, delivering an excellent user experience (UX) is crucial because it’s an important search ranking factor.

Core Web Vitals play essential roles in determining page experience success. They help quantify the UX of your WordPress website and point out areas to improve.

In this article, you’ll find all the information needed about Core Web Vitals. We’ll explain the definition of Core Web Vitals, tools to check the metrics, and tips to improve them.

What Are Core Web Vitals?

Google Core Web Vitals are performance metrics that measure the quality of website UX.

Google says that metrics making up Core Web Vitals may evolve over time. Currently, there are three Core Web Vitals metrics:

  • Largest Contentful Paint (LCP). A measure of a web page’s loading time. An ideal LCP should be within 2.5 seconds after the page starts loading.
  • First Input Delay (FID). A metric for a site’s interactivity and responsiveness. A page should have an FID of up to 100 milliseconds.
  • Cumulative Layout Shift (CLS). A measure of visual stability on whether users experience unexpected layout shifts on the page. This metric score should be 0.1 or less. 

Google has used Core Web Vitals as a search ranking factor since mid-2021, along with other page experience elements, like mobile-friendliness and HTTPS.

By knowing their site’s web vitals score, website owners can make strategic changes to their WordPress websites and have a better chance to rank higher on Google.

For example, if the web vital checker tool detects problems in the server response time, you may want to upgrade to a more extensive hosting plan or migrate your site to a reliable wordpress hosting.

How to Test Core Web Vitals

There are several popular tools to perform Core Web Vitals tests, including:

  • PageSpeed Insights. Copy and paste a web page URL and click Analyze. The tool will generate a Core Web Vitals score on mobile and desktop versions and provide suggestions on how to improve performance.
  • Google Search Console. See the Core Web Vitals report under the Enhancements section. This tool checks all URLs of your site, so there’s no need to copy and paste every URL like with PageSpeed Insights.
  • Web Vitals Chrome extension. Install this extension and it will show Core Web Vitals scores of your site and competitors’ websites.

Note that the Core Web Vitals score may vary on different tools, depending on various factors like timing, traffic, and users’ environmental conditions like internet connection. Also, a URL needs to be live for over 28 days to show an accurate Core Web Vitals report.

How to Improve Core Web Vitals on WordPress Sites

After knowing the score, let’s identify and troubleshoot any issues. This section will explain common causes and solutions for each Core Web Vitals metric.

How to Improve Largest Contentful Paint (LCP)

Slow servers are one of the most common causes of poor LCP. The longer it takes the Google Chrome browser to receive content from the server, the longer it takes to load web pages.

Follow these practical tips to optimize your server response time:

  • Use caching. Caching stores static data temporarily so it can appear faster when a user revisits the site. Top WordPress caching plugins are W3 Total Cache and LiteSpeed Cache.
  • Apply a Content Delivery Network (CDN). A CDN refers to server networks distributed in different locations. It helps a user’s browser receive copied content faster from a nearby server by cutting the data travel time.

Another culprit for poor LCP is slow resource load times due to large images or a lot of code above the fold – the area shown at the top half of a web page.

To solve this problem, compress images using an image optimization tool or plugin, like Squoosh or Imagify. Also, consider reducing the number of elements above the fold, including embedded videos and custom widgets.

How to Improve First Input Delay (FID)

JavaScript execution is the primary determinant of FID. When a browser deals with heavy JavaScript files, it can’t process other requests simultaneously. This can cause longer loading times and poor interactivity.

Therefore, pick a WordPress theme with simple layouts and avoid implementing unnecessary styles like animations or decorative features. You may also want to reduce unessential plugins that add unnecessary JavaScript files.

Another solution is to use code splitting to divide longer code into smaller chunks to ensure they don’t block the rest of the page from loading. Applying async or defer for unnecessary scripts can also be a solution. It tells browsers that a script won’t change the layout, so it shouldn’t hinder the rendering process.

How to Improve Cumulative Layout Shift (CLS)

Images, ads, and widgets without dimensions are the most common causes of layout shifts.

For example, text in a blog loads first on a slower connection while the hero image or ad banner takes more time to appear. Without proper dimensions, the hero image or ad will push down the text, causing layout shifts.

Therefore, include height and width size attributes on your images and videos or reserve the required space with CSS aspect ratio boxes. This method ensures that the browser allocates a certain amount of space in the web page while the image or banner is still loading.

However, ad networks sometimes don’t provide the correct size for their slots and may display an ad with bigger pixels. In this case, set Overflow Hidden or oversize the ad container.


Core Web Vitals are Google’s initiative to measure a website’s UX performance. Knowing these metrics is important because Google considers Core Web Vitals a search ranking factor.

Three Core Web Vitals metrics are loading (LCP), interactivity (FID), and visual stability (CLS).

Here are the common issues of each metric and how to solve them:

  • LCP. The main culprits are slow servers and resource load times. Ways to solve them are using caching, a CDN, and compressing images.
  • FID. This metric’s common issue is related to heavy JavaScript files. To tackle the problem, reduce unnecessary plugins, avoid a complex theme, and use code splitting.
  • CLS. A poor CLS can be the result of images or ads without dimensions. Therefore, include size attributes and use reserved ratio boxes to improve CLS.

That wraps up this article about Core Web Vitals. Now, it’s time to put these tips into practice and boost your Core Web Vitals score. Good luck!

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