What Are Core Web Vitals? Why Are They Important?

core web vitals

Google uses top-secret algorithms and ranking systems to organize the hundreds of billions of web pages available on the web and to make the information database universally readily available to people. It presents the most relevant and useful results in a fraction of a second to the searchers. Here Web Vitals is landmark announcements from Google to help you understand how they evaluate your site in terms of performance and user experience. With Web vitals, Google is specifying three new metrics  LCP, FID, and CLS also known as the Core Web Vitals to represent the best available signals developers can use to figure out their site’s quality of experience across the web. Web Vitals and Core Web Vitals provide insightful data to help develop awesome sites that will be valued by both Search engines and users. 

Evolving Web Vitals – Improving the Digital Experience

User Experience is always the most crucial part of a website. Optimizing for UX is a key to the success of any site on the web. Google always endeavors to improve users’ search experience and to deliver the most optimum SERP when users google anything. And Google search favors websites with great UX.

Google & other search engines always focus on ensuring that people access the right information they need. At the same time, browsers pay special attention to selecting the websites that will convey a delightful user journey. They follow user-oriented approaches and technologies for developing a better web. Search engines constantly update their algorithm to rank up the finest ones and push back the low-grade websites. 

In the light of the foregoing, In May 2020, Google announced about page experience update and a new set of performance metrics. Its named Core Web Vitals. The update began rolling out in June 2021. 

Core Web Vitals are the subset of Web Vitals that apply to all web pages, should be measured by all site owners, and will be surfaced across all Google tools. Each of the Core Web Vitals represents a distinct facet of the user experience, is measurable in the field, and reflects the real-world experience of a critical user-centric outcome.


Here is a comprehensive guide on Google’s 2021 Core Web Vitals:

What Are Core Web Vitals?

Core Web Vitals are a set of specific factors depicted by Google to evaluate a webpage’s overall user experience. It helps to quantify the page experience and identify opportunities to improve based on the three aspects of UX; page loading time, page interactivity, and the visual stability of a webpage as it loads. 

Developers and website owners can utilize these metrics to understand their user’s real-world experience on a webpage.

These metrics provide measurable SEO performance scores that define how well your webpages are performing from the users’ perspective. Core Web Vitals test result specifically shows every element which is affecting the UX. So that site owners can identify and fix the technical issues.

 What Are the Different Core Web Vitals Metrics?

To measure the three essential aspects of page experience; loading performance, responsiveness, visual stability; Google chooses three corresponding metrics:

  1. Largest Contentful Paint (LCP)
  2. First Input Delay (FID)
  3. Cumulative Layout Shift (CLS)

Largest Contentful Paint (LCP)

Largest Contentful Paint, or LCP, refers to webpage loading performance. 

LCP is the time from clicking a webpage’s link to seeing the largest content in the viewport complete and ready for interaction. 

It measures the time how long a webpage takes to render its all above-the-fold content and nothing below the fold is considered. The metric calculates the loading time of the content that appears without scrolling and is relevant to the user experience.

The types of elements considered for Largest Contentful Paint are:

  • Images
  • <img> elements that are inside an <svg> element
  • Image tags.
  • Video thumbnails
  • Background images with CSS
  • Block-level elements, text elements such as paragraphs, headings, lists, etc.

What Is a Good LCP Score and How to Improve LCP?

To provide an optimal user experience LCP should be less or equal to 2.5 seconds. 

  • If a webpage scores less or equal to 2.5 seconds, it will get a green grade and the score is good to go. It means it passed the assessment.
  • If LCP is between 2.5 and 4.0 s, it will get an orange grade and the score “needs improvements”.
  • If the LCP is more than 4 seconds, it will get a red grade and the score is poor. It means it fails to pass the assessment and needs to fix issues shortly.

Here are some tips to improve your site’s LCP:

  • Removing unnecessary third-party scripts and large page elements: third-party scripts and large elements slow down a page’s LCP.
  • Choose better hosting service provider and enable page caching. Its helps to improve the Time to First Byte and Reduce Server Response Time
  • Image Optimization: It is recommended to compress and scale images in such a way that the images are displaying only as large or small as required. The smaller the image dimension is, the faster the loading time will be.
  • Minifying CSS and JS files
  • Defer Non-Critical CSS, Inline Critical CSS, and Remove Unused CSS
  • Defer JavaScript and Remove Unused JavaScript
  • Use a CDN: CDN helps users to access a site quickly and easily. It reduces the round trip time(RTT) or the length of time between the user request and the server response. 
  • Use Preload for Critical Assets and Optimize for above the fold: To improve your LCP score, you should always optimize the above-the-fold content and make the critical assets load as fast as possible.

Cumulative Layout Shift (CLS)

Cumulative Layout Shift, or CLS, refers to visual stability. It measures how stable a webpage is as it loads. It measures if there is an unexpected shift in the content while elements of a webpage such as images, buttons, text are loading.

If elements of your webpage move abnormally, you will get a high CLS score, which is bad for both SERP ranking and user experience. The elements of a website must be stable and move fairly to avoid complications in accessing a webpage.

The reasons for Cumulative Layout Shift are:

  • Images with no specified dimensions
  • Advertisement, Embedded content, and iframes without specified dimensions
  • Dynamically injected content
  • Web Fonts causing FOIT/FOUT (Flash of Invisible Text / Flash of Unstyled Text)
  • Actions waiting for a network response before updating the Document Object Model (DOM)
  • Contact forms, buttons, and other kinds of content

What Is a Good CLS Score and How to Improve CLS:

The recommended FID score is 0.1 or lower for a better page experience.

  • If the CLS score of a webpage is 0.1 or lower, it means the page gets a green grade and it passes the assessment
  • And the CLS score of a webpage if is between 0.1 and 0.25, it means the page gets a yellow grade and it needs improvement
  • Or the CLS score of a webpage is above 0.25, it means the page gets a red grade and the score is poor

Here are some tips to improve your site’s CLS:

  • Properly scale and define the size for media such as video, images, GIFs, infographics, etc
  • Reduce third-party scripts and minimize JavaScript as much as possible.
  • Never insert content dynamically above existing content.
  • If using CSS to animate elements, prefer “transform” animations.
  • Use system fonts when possible and preload your fonts so that the font assets will be downloaded and rendered as a priority asset

First Input Delay (FID) 

FID measures how long it takes for the browser to respond when a user tries to interact with the webpage such as clicking on a button or entering an email address into the popup box. It only scans the performance for the events like clicks, and key presses by the users. 

FID score determines how efficiently your webpage is interacting with users and how long it takes something to happen on a page. Google takes FID as an important metric because it shows how easily and swimmingly real-life users can engage with a website. 

The types of interaction considered for First Input Delay are:

  • Clicking on a link or button
  • Choosing a menu item in a dropdown
  • Entering email into a form field
  • Opening the “accordion menu” on a mobile device

What Is a Good FID Score and How to Improve FID?

The fair FID score is 100 milliseconds or less for providing a better page experience.

  • If the FID score of a webpage is 100 milliseconds or less, it means the page gets a green grade and it passes the assessment.
  • And the FID score of a webpage if is between 100 to 300 millisecond, it means the page get a yellow grade and needs improvement.
  • And other hand the FID score of a webpage if is more than 300 millisecond, it means the page get a red grade and the score is poor.

Here are some tips to improve your site’s FID:

  • Minimize JavaScript and CSS
  • Remove unnecessary JavaScript and CSS and any non-critical third-party scripts
  • Use a browser cache
  • Keep request counts low and transfer sizes small

Why Are Core Web Vitals So Important?

Google is always user-centric. It put the customer’s advantages at the heart of its development process. Google wants to serve the searchers exactly what they are looking for and in the meantime let them get a pleasant journey on the site they are entering. 

In June 2021, Google declared Page experience as an official ranking factor. Page experience is measured in terms of so many metrics such as Mobile-friendliness, Safe and secure browsing with HTTPS, lack of intrusive interstitials, etc. And recently core web vitals metrics are considering as the most heavily weighted ranking aspects. These metrics help to discover what your real users are experiencing. The detailed report and recommendations are really helpful for improving the overall quality of a website.

Google inspires site owners, developers, and designers to follow the best practices to facilitate the users with a smooth and impressive user journey. Optimizing Core Web Vitals metrics score will enhance the Page Experience significantly.

The most notable importance of core web vitals are

  • Core web vitals are important for SEO
  • Insightful data helps to keep page content organized and clean
  • Improve websites visibility and ranking
  • Ensures pleasant User experience
  • Great user experience means more traffic and more gains

Tools to Check Core Web Vitals 

To get the insightful data and to see how well your website performs in terms of core web vital and page experience, you should analyze your website using 

website performance analysis tools. These tools provide an easy way to conduct a website performance test and analyze different metrics which are affecting the performance and fix the issues to optimize the score.

Here are some of the best tools to check Core Web Vitals for your site:

Wrapping Up Discussion

Web vitals are the ranking factor determined by google to enable site owners to quantify their page experience score and take initiative to improve the UX.

Every website owner should focus on improving core web vitals to make their site rise up on the SERP ranking. The better the UX of your site, the higher the success rate of your site.

The improvement on core web vitals metrics LCP, FID, and CLS will proportionally improve both your users’ experience and your rankings. 

Not to mention, Google provides resources, tools, and data to guide and simplify the task of analyzing the page experience of websites that site owners deliver to their users. They can easily identify and focus on the weak points that are worsening the UX of their site. Core Web Vitals or Google’s page experience metrics are the center of focus for enriching UX, engaging more users, getting repeat visitors, and gaining long-term success.

At Just Creative Studio, our SEO enthusiast can help you grow robustly. If you’re finding it hard how to analyze and improve the core web vitals of your site, don’t hesitate to contact us. We have a team of professionals who can support you from designing your dream website to making it a revenue-generating machine overnight!

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