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Summary: Core Web Vitals will be a ranking factor by 2021. This guide talks about Core Web Vitals in general, how to measure and improve Core Web Vitals for better rankings.

Google is making constant modifications to its algorithms to ensure that the users have the best experience while searching for anything on the search engine. 

To enhance the speed, stability, and responsiveness, Google announced the addition of new metrics in May 2020. These new parameters, termed as Core Web Vitals, are set to be released in the May of 2021.

After this new implementation, the user experience signals will combine the scores to rank the webpage. To help the publishers, Google has also released different tools that you can use to improve the user experience.

What are Core Web Vitals?

Core Web Vitals comprises particular factors that Google deems important for the best user experience in a webpage. The Core Web Vitals gives utter importance to visual stability, interactivity, and loading time. 


There are three distinct Core Web Vitals: 

  • Largest Contentful Paint (LCP), 
  • First Input Delay (FID), and 
  • Cumulative Layout Shift (CLS)

Google observed that a higher loading time of the page is directly proportional to the bounce rates. After a deep analysis of the industry, they found that web pages needed some guidelines to provide a better user experience. 

For this, Google launched the latest Core Web Vitals parameters that every website has to pass to get a better ranking on the search page.

Why are Core Web Vitals important?

With Google’s plans of making user experience a legit ranking factor, Core Web Vitals is important for enhancing the user experience. After Google releases the new metric sets, the latest user experience signals will combine:

  • Safe-browsing: With the aid of safe browsing, users can fix the security problems within their websites. The information that safe browsing offers include URLs, Help Center articles, etc. It helps them to understand, diagnose, and then fix the security issues.
  • Intrusive interstitial guidelines: Several intrusive interstitials can contribute to poor user experience. For example, pop-ups that block the main content, etc. With this feature, Google aims to improve the search experience of mobile users.
  • Mobile-friendliness: Google introduced mobile-friendliness as a ranking factor to help users gain access to high quality and relevant search results. These ensure the proper configuration of a site and enhance the ease of viewing on mobile devices.
  • HTTPS security: HTTPS adoption is a vital criterion that Google looks at while ranking. Right now, HTTPS offers excellent security and performance and comes with numerous benefits that assist site conversions. You can conduct the transition without affecting the traffic and search ranking.
  • Core Web Vitals: These are the latest metric sets that are considered to be a part of the ranking signals that Google uses to prioritize the search results. These consist of LCP, FID, and CLS. With the help of these tools, users can now make the necessary changes with ease.

The inclusion of Core Web Vitals is an indication of its importance in ranking websites. Now, the impact of Core Web Vitals on online traffic will have a direct effect on your business. 

As per Google studies, the web pages that can meet the criteria of all three subsets of the Core Web Vitals have a 24% less chance of visitors leaving their sites. This statistic is huge as it means you are likely to gain it just by making some adjustments.

Even without the statistics, improving the user experience will only bring efficiency to your virtual business presence. Moreover, it is also considered as a factor crucial to meet if you want the site to make an appearance on the Google Top Stories.

Google has reported that good page experience is not the only thing that matters. It is among 200 other factors that the search engine giant uses to prioritize sites. However, it is undeniable that having a better page experience will boost your rankings.

What’s inside Core Web Vitals?

The three components of Core Web Vital:

1. Largest Contentful Paint (LCP)

Largest Contentful Paint (LCP) measures how fast a web page can load. 

In layman’s terms, it is the duration of time from opening a link to viewing the content on the screen. You can check the LCP score with ease. 

Click on the Google PageSpeed Insights, and you could check the score. Another way is to go to the Google Search Console Tools, where everything about Core Web Vitals will be available in detail.

The ideal time for LCP is within 2.5 seconds. Anything more than that will fall under the category of “needs improvement” or “poor”. It is Google’s way of guiding you to boost your website’s UX. Now, this might become an issue if you have numerous high-resolution images or videos on the web page.

Let’s talk about the various elements that are taken into consideration for the Largest Contentful Paint. 

  • Block-level elements that contain inline-level text elements children or text nodes
  • Image elements
  • Video elements
  • Image elements within an SVG element
  • An element that has a background image, which is loaded with the assistance of the URL function

Google reported that it incorporated such restrictive inclusions to ensure simplicity. However, they also said that new elements might get added as the research is still ongoing.

The element size that LCP considers is the one that the users view within the viewport. However, if the elements remain outside the viewport, those parts are not reported.

2. First Input Delay (FID)

First Input Delay (FID) measures the interactivity quotient of the webpage. Here, the duration of time that a user needs to interact with the page is taken into account. Now, the interactions include entering an email id, clicking on a hyperlinked site, selecting an option, etc.

In the case of FID, the ideal time is 100 milliseconds or less. If it is more, Google will either rank it in “needs improvement” or “poor”. It is a critical factor for login pages.

While FID surmises taps, key presses, and clicks as first inputs, it does not take into account zooming or scrolling. Any input delay can indeed contribute to a poor user experience. But, various reasons explain why the first input delay is vital. Some are:

  • The first input delay creates the first-ever impresser of a user. It will tell the user about the reliability and quality of a particular website.
  • Focusing on the FID and its improvement can enhance the interactivity of the entire web as a whole.

3. Cumulative Layout Shift (CLS)

The Cumulative Layout Shift (CLS) is a measurement of the webpage’s stability. In simpler terms, it is determined if the element of a particular page shifts after the loading ends. As per Google, the less the CLS, the better is your score.

The ideal CLS is less than 0.1. Now, if it is more than that, then Google will either defer to it as “poor” or” needs improvement”. CLS is vital as it ensures that the users do not have to run the risk of clicking something they didn’t want or forgetting what they saw.

To determine the layout shift score, two factors are considered. The movement of the unstable elements within the viewport between the rendered frames and the size of the viewport is taken into account by the browser. It is a multiplication of the distance fraction and the impact fraction.

The distance friction is a measurement of how much distance the unstable elements have shifted concerning the viewport. And the impact fraction is a measurement of the impact that the unstable elements have on the viewport between the two rendered frames.

Tools to measure Core Web Vitals

There are different tools that you can use to measure Core Web Vitals. These can be divided into two distinct categories – lab tools and field tools.

The lab tools include – Chrome DevTools, Lighthouse, and Total Blocking Time (TBT). And the field tools are Search Console, Chrome User Experience Report, PageSpeed Insights, etc.

Check out some of the tools listed here.

1. Lighthouse

Lighthouse is an automated lab tool that you can use to improve the quality of the web pages. It is open source and can be run against different web pages, regardless if it is public or needs authentication.

There are different variants of Lighthouse that you can choose from. You can use:

  • Web UI- With Web UI, you can run lighthouses as well as link reports without the need of installing anything.
  • Chrome DevTools- Here, you can audit the pages that need authentication with ease. Moreover, you can also read the reports in a format that is easy to navigate.
  • Node module– With this, you can ensure the easy integration of the lighthouse into the existing integration systems.
  • Command-line- In this case, you can ensure that the lighthouse runs are automated with the assistance of shell scripts.

2. Chrome User Experience Report

The Chrome User Experience Report is, by far, the most vital tool that you can use to measure the Core Web Vitals. It is because this tool shows you the actual data. Here, you can see the scores and the trifurcation of either good, poor, or it needs improvement.

You can access this data source with relative ease. It is available for the public and is accessible when you request a query to the BigQuery. Now, one of the best ways to check out this data is by visiting Google’s Data Studio Report.

However, there are certain things that you must consider. The scores are given for the entire domain. It is not restricted to a single homepage.

3. Search Console

While Google is getting ready to launch the new Core Web Vitals, it has also upgraded the performance table found in the Google Search Console. 

Core Web Vitals Search Console

You can find it under the “Enhancements” tab of any verified profile. It is a great tool to gather more information for making necessary improvements.

How to improve Core Web Vitals?

There are various ways to improve the Core Web Vitals. Check out some of them listed here for each sub-set.

1. Improve Largest Contentful Paint (LCP)

The best way to make changes is to understand the reasons that cause poor LCP. Some of them include – client-side rendering, the slow response time of servers, CSS blocking time, etc. Now, you can establish lazy loading on your web page. 

It means that the images will only appear when the user scrolls down. By doing this, you can attain fast LCP. Another thing that you can do is remove the elements that are weighing down the loading time. Moreover, you can also opt for a better web host. If you are on WordPress, check out Largest Contentful Paint WordPress guide for practical ways to improve LCP.

Third-party scripts can also slow down the loading time of a web page, and removing them will help you increase the LCP score significantly.

2. Improve the First Input Delay (FID)

When it comes to First Input Delay (FID), the prime reason for the low score is the huge JavaScript execution. If you work on this, your score will improve substantially. 

You just need to break up the long-running codes, which will delay the JavaScript that was directed to load on a webpage. Now, if you break it into small tasks, it reduces the input delay on the website.

Similar to LCP, third-party scripts have a significant negative impact here as well. It can reduce the score, and thus, it is advisable to remove them. Another way that you can enhance the score is to use the browser cache. You can also reduce the work of the main thread and ensure that you are not transferring huge files.

3. Reduce Cumulative Layout Shift (CLS)

There are multiple ways that you can reduce the Cumulative Layout Shift (CLS). The foremost thing that you need to do is set dimensions for different types of media such as images, iframes, infographics, ads, etc. 

Moreover, you must avoid putting new information over the existing one. If you want such affordances, then you must allow space for it in the viewport.

Web fonts can also lead to layout shifts. It can happen in two distinct ways – FOIT (flash of invisible text) and FOUT (flash of unstyled text). 

Various tools can help you reduce these issues. Furthermore, animations can also trigger changes in the layout. It is advisable to opt for the transform animation instead of the animation of properties.


In essence, the Core Web Vitals are Google’s effort to maximize user experience. 

Always remember, the better UX you have, the more will be your page experience score. It will help you to gain more relevancy when users search sites on Google. 

Though it will not automatically make your site come at the top, it surely impacts your visibility over search engines.

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