Is Your Website Sick? How Google Core Web Vitals Affect It

Table of Contents

Core Web Vitals have recently become the center of attention as Google has rolled out a few changes on its latest update. In more detail, Google will now use page experience as ranking signals for search results. 

Page experience includes Core Web Vitals and some other elements that influence user experience on a website. The implementation of this new update started in May 2021 and it is expected to be completed by the end of August.

The new update has undeniably highlighted the importance of Core Web Vitals for a website. In this article, you will learn more about Core Web Vitals and how to check them, as well as the other UX factors that will affect the ranking of your website. 

What Are Core Web Vitals?

Core Web Vitals are some metrics that Google has classified to measure the overall user experience of a website. By keeping track and improving these metrics, websites can offer a better page experience to their visitors. Moreover, with the implementation of the new Google update, websites with optimized Core Web Vitals will also gain a better ranking in searches. 

The metrics included in Core Web Vitals are the largest contentful paint, first input delay, and cumulative layout shift.

1. Largest Contentful Paint (LCP)

The largest contentful paint, or LCP, is a metric that measures the time it takes for the largest content or graphic element to load. In essence, it measures how long it takes for the main content to finish rendering on the user’s screen and the visitor can interact with it.

According to Google’s guidelines:

  • LCP is good when it is less than 2.5 seconds for 75% of page loads,
  • LCP needs improvement if it takes between 2.5 and 4 seconds, and
  • LCP is poor when it is longer than 4 seconds.

The most common reasons why the LCP is poor include slow server response times, slow resource load times, and render-blocking JavaScript and CSS.

2. First Input Delay (FID)

Even though the largest contentful paint measures the time that the largest content element needs to render on a screen, it doesn’t measure the page’s responsiveness.

Hand holding using mouse clicking

First input delay, or FID, is a metric that measures how quickly the page is responding to the user’s interaction. It represents the period between the user’s first interaction with the website and the browser’s response to that interaction. 

According to Google:

  • FID is good when it is less than 100 milliseconds for 75% of page loads,
  • FID needs improvement if it is between 100 and 300 milliseconds, and
  • FID is poor when it is more than 300 milliseconds.

Poor FID is mostly caused by heavy JavaScript execution.

3. Cumulative Layout Shift (CLS)

Cumulative layout shift, or CLS, is a Core Web Vitals metric that measures the instability of the content within a website. This metric will sum all layout shift scores for every unexpected layout shift during user navigation.

“Google will now use page experience as ranking signals for search results.”

The layout shift score is calculated by the size of the visible viewport and the distance of the shift. 

According to Google’s specifications:

  • CLS is good when it has a score of 0.1 or less for 75% of page loads,
  • CLS needs improvement if it has a score between 0.1 and 0.25, and
  • CLS is poor if the score exceeds 0.25.  

The main causes of poor CLS include the use of images, ads, embeds, and iframes without dimensions, and dynamically injected content among others. 

What Other Web Vitals Affect Your Website?

The three Core Web Vitals metrics will join the other UX-related factors that have already been used as ranking signals in searches. The latest Google update will still take all of these elements into consideration. 

These UX-related factors include mobile friendliness, HTTPS, safe browsing, and no intrusive interstitials.

1. Mobile Friendliness

This element refers to a website’s optimization for viewing on mobile devices. This means that all elements of a page must load properly on the smaller screen size of a mobile phone or tablet.

Using Cell Phone
Using Cell Phone

Considering this element, it becomes apparent that mobile usability has become more important than ever. 

A few things that you can do to improve your website’s mobile usability are:

  • Optimize compatibility with numerous devices and browsers,
  • Adopt responsive design that can account for varying screen resolutions,
  • Format the visual elements accordingly, and
  • Optimize for speed.


The HTTP protocol is now considered unsecure and outdated by the majority of browsers. For this reason, Google is checking whether a website has SSL/TLS protocol, which is the most secure connection. The HTTPS encryption can be easily spotted as a padlock icon will appear next to the website’s URL in the browser’s address bar. 

3. Safe Browsing

A safe browsing experience is a very important element for Google. With this term, we refer to all the security gaps of a website that might be viruses or malware. Every page shouldn’t have any malicious content that compromises the security of its visitors.

4. No Intrusive Interstitials

Intrusive interstitials are all the website elements that disrupt the browsing experience. These include various pop-ups and advertisements that cover the website content. This issue becomes even bigger on mobile devices’ screens as they often cover the entirety of it. 

However, it is important to note that the legally required interstitials are not considered an issue. For example, age verification blockers and cookie consent notifications will not affect the ranking of your website.

How to Check the Core Web Vitals of Your Website 

Now that you understand what Core Web Vitals are, you need to learn how to check if your website is working properly. Keeping Google’s latest update in mind, it has become clear that they will affect your website’s organic reach. 

To check the Core Web Vitals of your website you need to:

  1. Visit Google Search Console.
  2. Find the Enhancements menu and click on the Core Web Vitals. This action will load a report of all the affected URLs of your website.
  3. Moreover, you can also visit PageSpeed Insights to find mobile and desktop speed insights. This tool will break down each Core Web Vitals metric.

The latest Google update is placing user experience at the center, with Core Web Vitals taking up a very significant role. If you have any questions about improving your website’s metrics, contact our team to get ready for the update. 

About the author...
Stuart Brown
Stuart Brown
Stuart is the co-founder of Launch Experts. With 20 years of experience in the marketing industry, his primary focus is to break away from the traditional marketing agency model, ensuring clients get a positive return on investment from their marketing campaigns.