Google Core Web Vitals: the new Ranking Signals for SEO

Google Core Web Vitals: the new Ranking Signals for SEO

In their quest to make user experience when browsing more relevant and enjoyable, the search engine giant Google says it will make changes to the search engine ranking by integrating user experience into its SEO criteria.  

These algorithm changes, originally scheduled for May 2021, have been delayed until mid-June to give advertisers more time to master user experience concepts and to prepare for this major update. Core Web Vitals will become an important ranking factor along with the addition of two new performance metrics: the Cumulative Layout Shift (CLS) and the Largest Content Paint (LCP).  

In this article, our SEO experts explain the value of these new performance indicators as well as how to maintain your ranking and even rank higher in search engines.  


What are Core Web Vitals? 

Core Web Vitals, also known as Essential Web Signals, are a set of metrics that allow you to analyze and evaluate the UX performance of a website. To evaluate the quality of the user experience, these signals take into consideration three key indicators: page loading speed, interactivity time, and visual stability. 

  • LCP  

Le Largest Content Paint, or LCP, is an important, user-centric metric for measuring the perceived load speed. That is to say the time it takes for a web page to display the first visible content. 

A good LCP should have a duration of less than 2.5 seconds to display the first elements of the page. Up to 4 seconds, Google considers your page as moderately effective and recommends that you optimize the speed if you want to improve your position on the Search Engine Results Pages (SERP). When you have an LCP of more than 4 seconds is considered poor. A bad LCP can have negative consequences on your SEO.  

  • FID  

FID or First Input Delay is an indicator that will analyze the interactivity delay, i.e., the time it takes between the moment a visitor interacts with a web page to the time it takes for the browser to respond to this interaction. For example, FID can measure the time between when a user clicks on a link and when the browser starts loading the page in question. The ideal score for this indicator would be less than 100 milliseconds. If the FID registers a large delay, it may directly impact the conversion rate.  

  • CLS 

The CLS, also called Cumulative Layout Shift, is an indicator that checks the visual stability of a web page during the loading phase. Google will assign a score from 0 to 1 to the web pages and the CLS of a website should be between 0 and 0.1 to be optimal. If for example there are images, advertising integrations missing, and iframes without dimensions or dynamically injected content, this can impact negatively the CLS.  


Essential Web Signals to keep in mind 


It is important to note that Core Web Vitals will be combined with other elements that are already considered by the ranking signals, these are called “user experience signals”, and include: 


  • Mobile usability/friendliness: this is a ranking signal, announced in 2015, that prioritizes content that is easy to view on mobile devices. You can monitor your website’s mobile-friendliness in Google Search Console. 


  • Secure navigation: To resolve security issues on a website, webmasters can access a Google Search Console report that will help them to identify key issues including malware, misleading pages, harmful downloads, and unusual downloads.   


  • HTTPS Security: This ranking signal is less important than the content quality signals. However, it is essential to migrate all pages to HTTPS, not only because it can help your website to get a better ranking, but also because it is safer for visitors.    


  • Guidelines for Trouble Shooting (Pop-up): Webmasters should avoid as much as possible the use of pop-ups and banners that cover the main content of the page because this can result in disrupting and disturbing the visitor during their navigation.   


The impact of Core Web Vitals on your SEO ranking 

All the elements mentioned in the previous paragraph, as well as the new Core Web Vitals, are factors that will impact your SEO ranking as of mid-June 2021. User experience will have a bigger impact on the position of a website and the SERP.  

It should be noted that a website with bad Core Web Vitals will not necessarily be penalized. John Mueller, the spokesman for Google, confirms this idea by stating that the objective of the search engine is always to offer the best possible result to the queries of Internet users. Therefore, a website that has a poor score in the Core Web Vitals, but whose content is more relevant than another site, yet more ergonomic, will be prioritized and will continue to be ranked higher in the Google SERP. For website owners, this update represents the beginning of a big change in SEO. 

New Mobile Feature: Top Stories 

To enhance user experience, Google has also launched the “Top Stories” feature on mobile, which lists the top stories on Google News. This will no longer require the use of AMP (Accelerated Mobile Pages which is an online publishing format created by Google, to accelerate the display of pages on mobile devices). Indeed, from May 2021 onwards, non-AMP pages can be integrated and are now eligible for the Top Stories feature on Google Search. Google also says that pages that offer the best user experience will be prioritized, regardless of the technology used.  

Google also announced the design of a visual indicator on results pages to highlight websites that meet all the criteria of user experience. 

How to start optimizing Core Web Vitals? 


To optimize a website and take into account the Core Web Vitals, we recommend that you start by analyzing each URL on your website individually. When it comes to optimizing your pages, our experts recommend that you consider the following basic measures: 

  • Use images with the right dimensions 
  • Compress large image files 
  • Apply the lazy loading technique, which improves loading times, especially for websites with a lot of data such as images and videos 
  • Remove all unnecessary resources  
  • Offer images in formats that improve the loading time of a site 
  • Remove all unused javascript code 
  • Reduce the size of each page to less than 500 KB 
  • Keep the total number of resources per page to less than 50 (ideal for mobile devices) 


Tools to measure your Core Web Vitals score 


  • PageSpeed Insights 

It is the most used tool to measure Core Web Vitals. It offers a quick and detailed diagnosis of the UX performance of a web page, the results divided into two tabs: mobile and desktop, to identify the performance of each version separately. PageSpeed Insights shows you an overall score as well as detailed scores for each criterion. Each error identified is accompanied by tips on how to fix it. 

  • Chrome DevTools 

To have an in-depth analysis of the performance of a website, it is recommended to choose the “Performance” menu in Chrome DevTools to get detailed insights on the different elements to be loaded on the web page, as well as the time required for them to be visible. In case of long loading times, this tool is particularly effective in identifying problematic pages. 

  • Google Search Console 

Following this new update, Core Web Vitals results will be directly integrated into a dedicated menu in Google Search Console. The owner of a site will be able to quickly access the data related to it but also be alerted by e-mail in case of a problem, to solve it quickly.   

  • Lighthouse 

Intended for Google’s Chrome browser, this tool allows you to analyze a web page in one simple click. Just right-click and choose “Inspect”. In the menu that appears, you are invited to select “Lighthouse” to access this feature. You will then be able to choose which version of the site should be analyzed: mobile or desktop. Lighthouse also offers performance audits, usability testing, progressive web application audits, and SEO tools. 


In short, Google’s goal behind these updates is to create a digital ecosystem that is valued by users to ensure a relevant, enjoyable and efficient browsing experience. 

We hope that the information presented in this article will help you prepare for this new update.