Core Web Vitals: What They Are and Why They Matter

Have you heard rumblings of a Google ranking factor update this year? Last May 2020, the search giant announced that they are releasing a new ranking factor focused on overall page experience. Included in the update are three new key metrics that they'll be using to measure the performance of your site, which they call Core Web Vitals.


The three metrics include: Largest Contentful Paint (LCP) or page load speed, Cumulative Layout Shift (CLS) or visual stability, and First Input Delay (FID). Overall, the Core Web Vitals  aim to ensure that websites are providing a great user experience. It's nothing new but if you haven't been paying attention to these metrics, your rankings could inevitably suffer.


Core Web Vitals as a Ranking Factor

Google's aim is to ensure all indexed websites are offering the best possible experience for their users. By making Core Web Vitals as part of their ranking factors, the search giant is encouraging web developers, whether they’re from a web design company or freelancers, to focus and improve on UX. So, if you and a competitor site both rank for a particular keyword but you have better UX, Google will reward your site with a higher position on the search results for that specific keyword.


Now, to better understand the Core Web Vitals, let’s break down each of the three metrics:


  • Largest Contentful Paint (LCP)

This metric refers to page loading speed. In a nutshell, LCP measures the length of time it takes for all of a page's content (above the fold) to load. For instance, if you open an online clothing store and the first thing you see on the screen is a large image with all their product offerings, LCP measures how long it takes for that image to fully load on the page.


LCP can be affected by either client-side rendering or slow server response times. To provide an optimal user experience, LCP should occur within two seconds after the page has been opened.


  • Cumulative Layout Shift (CLS)

This key metric refers to visual stability. It measures how often content moves around a page and by how much. For instance, have you ever read an article only to have an image or ad load above the content you’re reading, causing the text to move down on the screen? Even worse, have you ever tried to click a link only to have something load and cause the link to move, making you click on the wrong thing?


CLS aims to provide a measurement for these unexpected shifts or movements in the layout, helping webmasters keep an eye on the frequency of users encountering poor user experience due to unstable elements. To meet Google’s standards, pages should have a CLS of less than 0.1.


  • First Input Delay (FID)

This metric refers to interactivity. It measures how quickly users can interact with the content on your site. For instance, if a user clicks on a link or a button that leads them to another page or a pop-up contact form, FID tracks the time it takes for the browser to lead them to the destination page or initiate that pop-up.


Your FID can be influenced by JavaScript issues (large JS files) or your browser trying to execute too many actions. For excellent user experience, it’s best to have a FID of less than 100 milliseconds for your website’s pages.


Why are Core Web Vitals an Important Ranking Factor?

Now that you know all about the key metrics of Core Web Vitals, why exactly should they matter in your SEO strategy?


For years, Google has been indicating that they prefer quality user experiences. The search giant is already using the following Page Experience metrics as ranking signals:



The Core Web Vitals are basically an extension of these Page Experience metrics. Google wants to ensure searchers land on websites or web pages that give them the answers to their questions while enjoying a pleasant browsing experience.


With the Core Web Vitals, the search engine is encouraging all web developers and site owners to follow the best UX practices. Once you meet their standards, that could be the tie-breaking factor between you and your competitor for a highly valuable keyword.


The Impact of Core Web Vitals

After the rollout of Core Web Vitals, you likely won't see a dramatic drop-off in your rankings and traffic. It will be a slow decline. Although if you've been having issues with your page loading speed and visual stability for some time now, you will be seeing a decrease in your rankings or traffic. After all, page load speed has been an important ranking factor for a while now. The Core Web Vitals metrics just enhance what Google is already measuring.


Optimize your site, continue to create great content, and never stop designing and developing your web pages for user experience. Once you have those in the bag, you'll always meet Google's standards.