05 / 11 / 2020

Core Web Vitals: What are they and how to optimize them?

Core Web Vitals in SEO

Optimize the quality of user experience

Google's goal is and has always been to optimize the quality of user experience. For this reason, Google has been investinga lot of time and resources in finding a formula to better understand the user experience on websites. Some examples of the tools promoted for this purpose are: Pagespeed Insights, Mobile-friendly Test, Lighthouse, AMP, the Chrome UX Report...

From here Core Web Vitals arise as a way to unify metrics and establish a easy and simple criteria that will define a good user experience. This criteria show us an important key to the long-term success of any site on the web.

Although in today's article as specialized  seo agency  we will get a little more technical, its content is aimed at everyone: whether you are a business owner, marketing manager, or programmer.

What Are the Core Web Vitals?

Let's start from the beginning: What are the Core Web Vitals?

As we have discussed previously, Core Web Vitals are a recent Google initiative that aims to provide a unified guide to quality signals in order to understand what metrics or actions we must take into account to offer an excellent user experience on our website.

In this way, we can easily identify which UX and WPO problems our website has and find the necessary actions to solve them.

Objectives of Core Web Vitals

This initiative has three main focuses or objectives:

The first, focus our attention on the user. Until now, we always thought only about time, and that is why we looked at metrics such as TTFB or HTML loading time. But the truth is that many of these do not indicate a key moment for the user neither affect him. For this reason, Google has brought us the CWVs to try to change this focus, and focus it totally on the user experience. Therefore, it is now necessary to base more on questions such as:

How long does it take to display the contents? How long does it take to load the top content of the page? Or how long does it take to be able to use the web? In summary : we go from looking at the loading time to the user experience.

The second goal is simplification . As we have already said, over time we have seen many types of indicators. In this way, the more than 15 indicators have been simplified in 3. Now these tools can not only be used by programmers or layout designers with technical knowledge but by all users in the world of digital marketing. 

The third objective is to help us optimize our web pages . Thanks to the tools provided by Google, we can see exactly in what way. We have control over the measures we are implementing.

Breaking down the CWV

Core Web Vitals are made up of 3 elements: LCP, FID and CLS . Each of them touches on an essential aspect of the web that if we are able to optimize it will help us not only to improve our SEO but to obtain a good user experience. Let's see them one by one!

FID or First Input Delay

Definition: Time it takes the browser from when an interaction is made (one click) until it is able to process it. Important to keep in mind, it does not measure the time until the element is loaded, but the time when it is able to process it.

Its importance : shows Google the impression that the user takes when they click. This time will vary a lot depending on the element, the browser and when the click is made.


Good: below 100 milliseconds

Can be improved: between 100 and 300 milliseconds

Bad: above 300 milliseconds

CLS or Cumulative Layout Shift

Definition: Displacement of the content of the initial load seen at the top. That is, from what you see in the first instance when loading until the page is fully charged, there should be as few changes as possible. This indicator is not over time.

Its importance : It is about avoiding the user frustration of clicking on the wrong element. Adding new elements or resizing existing ones does not count, unless their appearance moves existing ones.


Good: below 0.1

Can be improved: between 0.1 and 0.25

Bad: above 0.25

LCP or Largest Contentfull paint

Definition : Rendering or loading of the largest content element that is seen at the top of the page. It goes from when the web starts to load until that element is fully charged. This element can be a video, image, title...

Its importance : because it is a very important moment for the user since it constitutes the moment in which the user can begin to consume the content of the web. 


Good: below 2.5 seconds

Can be improved: between 2.5 and 4 seconds

Bad: above 4 seconds

Tips to improve Core Web Vitals

How to carry out the analysis of Core Web Virtals for your website?

First, we will be choose within our website a significant page for each group . For example, if we are talking about an online store, it would be the home page, one of category, subcategory (if there is one) and a product page. From here we must run the main Google tools (Page Speed ​​Insights and Lighthouse) in each of them, to be able to see where we are and what points must be improved.

Finally, it is highly recommended to review the competition's metrics using the same technic. The ideal would be to be able to make a comparison between your times and errors and those of your competition for each of the categories or groups of pages on your website. This means compare opur home page with our competitors' home page, our product page with their product page... and so on. In the end, we do not have to achieve perfection, but to surpass our competitors. 

Other aspects to consider

The FID is missing present in any of the tools since it is an element that depends on the real user. Therefore, to optimize it, we recommend that you look at the TBT (total blocking time) since it is an indicator that is very close.

On the other hand, it is important to analyze the different tests and comparisons with stable metrics and in a fixed environment. In other words, it makes no sense to test one day in one browser and another day in another. To do this, we recommend carrying out the tests through the tools that Google offers us and doing it in a specific order:

First, in order to analyze the user experience, we can see the data through Google Search Console, Web Vitals Extention and Page Speed ​​Insights. Once the points to change have been identified, we must apply the changes and carry out tests through tools such as Page Speed ​​Insights, Google Lighthouse and Chrome devtools. Google Lighthouse is a very good option since it performs the tests as if it were a Motorola G4 mobile with little processor and slow connection. To be able to look in other environments we have the option of doing it with Chrome devtools where you can choose the device and the type of connection to configure the environment completely.

How does Core Web Vitals affect SEO?

Core Web Vitals are NOT a positioning factor yet and do not affect SEO directly. However, Google has already announced that they will be included in their algorithm in the near future.

The latest news indicates that these will be included in mid-2021 (Google will notify 6 months before). As you can see, we have not a lot of time left and that is why there are many people are already working on it. 

So how can CWVs affect my website ranking?

When they are included, we can find two possible scenarios:

  • That they take part as a factor of ranking. In this case, the CWVs will be one more element that will help you to gain or loss positioning of your website.
  • Penalty Element. Having poor results in the various elements of CWV may make Google penalize you and make your rankings worse.

Either way, CWVs will play a very important role in our positioning, and we expect many changes in visibility and variations in SERPs when they are included.

Conclusion on CWV

  • Core Web Vitals are based on user experience and not just loading time.
  • Core Web Vitals were created with the goal of simplifying and helping to quantify the experience of our site and identify opportunities for improvement.
  • They are based on 3 elements: LCP, FID and CLS.
  • Always carry out our tests with the help of tools that allow us to set the elements of the environment.
  • CWVs do not yet directly affect the positioning of our website, but they will be able to do so from 2021.

Do you want to improve your Core Web Vitals metrics? In our agency seo in Barcelona ; we are specialists in helping all types of companies to sell online. All of our websites are designed to comply with Google's guidelines on speed and user experience. If you need a hand with the optimization of your web page or in improving its speed and positioning, do not hesitate to contact us. We will be happy to help you improve your sells!

Sergi Filella
About the author
Sergi Filella
Passionate writer and SEO preacher. My mission: rescue you from the forgotten depths of the second page of Google.

Related news

Hello! drop us a line

We use own cookies and thirds to offer you better service. More information about cookies