What are Core Web Vitals & How Can They Affect Search Rankings?

WebUpgrade Team

May 25, 2021

Last May, Google announced that page experience signals would soon begin to influence Google Search ranking. Almost exactly a year later, the search engine giant is rolling out its new ranking system to factor in various page experience signals, now including Core Web Vitals in ranking. Core Web Vitals are a measure of efficiency and speed that Google references as an indicator of page experience. Proper SEO practices can make or break your business, and this change represents a new way to stand out and get an edge on the competition in ranking.

What are Core Web Vitals?

Core Web Vitals are an assortment of three factors that measure speed and user interaction metrics for Google to get a better idea of potential user experience in search ranking. While user experience has long been a focus of most digital marketing agencies, its incorporation into the Google Search ranking massively increases its importance. The three Core Web Vitals add together with other web vitals such as mobile support, safe browsing, security, and a lack of intrusive popups to measure the experience a given user is likely to have on the site.

Though all the Core Web Vitals measure speed and interactivity efficiency, they all have specific interactions that their score hinges on. Examining each of the three Core Web Vitals can give us a better idea of how each one measures your site, and thus how to produce better SEO for a website.


Google measures loading speed as a value called “Largest Contentful Paint” (LCP). LCP is how long a webpage typically takes to load from the user’s end. This essentially measures the time it takes from a potential lead clicking on your link to when the full page has been loaded. Other speed metrics that Google and marketers have used in the past, such as First Contextual Paint (FCP) and Time to First Byte (TFFB), tend to measure actual transmission speed instead of speed from the perspective of an end user. This means that Google’s new use of LCP encourages developers and marketers to improve the experience for the actual user.

LCP is considered good by Google at a speed of under 2.5 seconds. Anything longer than 4 seconds is considered poor and will be penalized in ratings. This means that increasing your site’s speed is absolutely necessary to getting solid ROI on your content and to increase visibility from potential leads.

Visual Stability

Visual stability is measured using Google’s new ranking criteria as “Cumulative Layout Shift” (CLS). A higher CLS indicates poor loading visual stability, which will usually manifest itself as objects moving around on a user’s screen as content is loaded. Visual stability while loading has always been an important factor in digital marketing, as stable web pages increase the quality of a user experience massively, make sites easier to navigate, and reduce mis-clicked links.

Now that Google is factoring in CLS score into search engine ranking, it’s more essential than ever for healthy SEO. A higher CLS score indicates a less visually stable load for a page, thus ranking higher. Using defined sizes for images and other objects on a page can help limit this score, as can clearly reserved space for loading ads and other assets on a page.


Interactivity is measured as “First Input Delay” (FID) which measures the time it takes for a user to actually be able to interact with a page. Interaction can refer to any number of activities a user may take on a page, such as clicking a link, expanding a list, choosing menu options, or entering data into a form. Google’s new focus on this is an attempt to encourage SEO that focuses on how users actually interact with pages so that search rankings can present convenient and accessible options to users.

For pages where no interaction is required, such as blog content, FID may not play as much of a key role as other Core Web Vitals. For sites that rely on a user interacting with a page, however, it’s an important speed test that will have a large impact on ranking. The FID measures the speed of load in a way, but rather than simply measuring page load speed like LCP, it specifically measures interactive elements that are useful to the user. A speed of 100ms or less is considered good for FID, whereas a speed of more than 350ms will need significant improvement to get the best ranking possible.

Why are Core Web Vitals important?

As Google’s ranking is now incorporating Core Web Vitals into their overall use experience rankings, they are absolutely essential to getting quality SEO ranking and thus solid ROI for marketing and content efforts. Beyond just the SEO, however, Core Web Vitals are extremely important because user experience and site efficiency is an essential factor in engaging audiences, and potentially converting leads. Your website’s accessibility, ease of use, and first impression for the user can potentially make or break the buyer’s journey for that particular user. Now that Google is including these factors in ranking, they are doubly important to a healthy and robust brand and web presence.

Improving user experience

Due to user experience’s effect on CTR and engagement levels, Core Web Vitals were always important indicators of how accessible your site is to users, and what kind of the first impression you give. With Google now considering these as essential to user experience ranking, however, you cannot afford to neglect these doubly important factors.

Speeding up your site for a smoother user experience cannot be neglected any longer by organizations. At WebUpgrade, we’re experts in SEO and know how important speed, stability, and user experience have always been to the digital marketing equation– now more than ever.

The Future of SEO

Google believes that “Optimizing for these factors makes the web more delightful for users across all web browsers and surfaces, and helps sites evolve towards user expectations on mobile,” according to their initial announcement about the change in May 2020. Improved usability across the entire infrastructure of Google Search on the internet is good long-term for all marketers and developers.

The inclusion of Core Web Vitals into search ranking offers a unique opportunity for sites with well-planned and developed sites to get an edge on competitors while also offering a better user experience to visitors. Prioritizing the end-user experience more in ranking improves the quality of results in the future for the entire search engine ecosystem which benefits everyone.

How do Core Web Vitals affect SEO?

While Core Web Vitals are incredibly important parts of Google’s measurement of user experience, these factors are combined with other variables to create an overall score for user experience. Core Web Vitals may represent the lion’s share of this score, but it’s influenced by other factors as well, including:

  • Mobile support. Support for mobile devices is treated as an important signal for user experience and will increase your overall score.
  • HTTPS. Secure sites are considered a better experience for users, as many avoid unsecured sites entirely. Ensuring that all addresses in your infrastructure are HTTPS pages will help your user experience score.
  • Safety. Any malware on your site can seriously decrease your user experience score for obvious reasons. Safe browsing is essential to a positive user experience with your content, and Google ranks accordingly.
  • No interstitial pop-ups. Pop-ups that overwhelm the page and are a nuisance to users will have a negative effect on Google’s ranking. As these pop-ups can be incredibly frustrating for users, good content avoids these overbearing ads.

While those factors definitely play slightly into a user experience score, Core Web Vitals have massive effects on your user experience ranking comparatively. These other factors are important things to bear in mind when planning your site and content, but if Core Web Vital scores are underperforming, all SEO ranking will.

Speed up your site to ramp up ROI

Google’s Search algorithm acts as a gatekeeper in modern digital marketing, and quality ranking can expose you to new leads and increase ROI. With the addition of Core Web Vitals into Google’s ranking ecosystem, improving user experience by increasing the speed and efficiency of your content is extremely important to stay relevant under the new ranking criteria.

Developing quality SEO is incredibly important, and now the speed at which your site loads from the perspective of an end-user is inextricably linked to your search ranking. Increasing these speeds gives you an opportunity to gain ground in your search engine optimization efforts, while also making a better first impression on visitors and potentially increasing CTR.

Here at WebUpgrade, we offer a proprietary speed plug-in that can make your site among the fastest on the web. This will ensure that you get quality scores on Core Web Vitals and that the user experience of your site makes it easier for you to successfully convert leads. We’re experts in SEO and web speed, and our proprietary technology can be leveraged to guarantee that your site lives up to the highest of Google’s SEO expectations for user experience. If you’d like more information on how we can help speed up your site, or you have any questions about how Core Web Vitals affect you and your SEO, don’t hesitate to contact us today.

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