Core Web Vitals for SEO: An Overview

There are a great many things that go into designing a webpage that offers a good user experience. How fast the page loads and how easy it is to interact with the page are just a couple. And the list is constantly evolving.

Google defines the core elements of a webpage that enhance user experience as “core web vitals.” Core web vitals were introduced in Google’s page experience ranking update</a, which rolled out June–August 2021. And there is a strong indication that they will significantly impact SEO and how websites rank in Google.

In this article from our series on the page experience update, I’ll discuss core web vitals and how they factor into SEO.

What Are Core Web Vitals?

Core web vitals are a series of signals that help assess a webpage’s usability. These “vital signs” are page-quality signals that contribute to a good user experience. And that’s good for SEO.

Core web vitals cover things like page load time, responsiveness, and the visual stability of content. Google’s current set of core web vitals includes:

  • Largest contentful paint (LCP): LCP measures how fast the webpage’s largest image or text block renders. And Google recommends that it happen within the first 2.5 seconds.
  • First input delay (FID): FID measures load responsiveness. This refers to how quickly a webpage loads and executes so that the user can interact with the page.
  • Cumulative layout shift (CLS): CLS measures unexpected layout shifts on a webpage. One example is when a button or link shifts on the webpage, causing a person to click on something other than what they wanted.

Each of these core web vitals has specific thresholds that your webpages must meet at least 75% of the time, which I’ll go into in more detail in future articles. Doing so can earn your webpage a slight ranking boost.

Core web vitals thresholds chart from Google.
Image credit: Web Vitals, Google Developers

You can expect the core web vitals to evolve over time, but not without warning. According to Google:

… Core Web Vitals represent the best available signals developers have today to measure quality of experience across the web, but these signals are not perfect and future improvements or additions should be expected. … developers should expect the definitions and thresholds of the Core Web Vitals to be stable, and updates to have prior notice and a predictable, annual cadence.

How Might Core Web Vitals Impact SEO and Rankings?

Core web vitals help ensure the user experience with your site is fast, responsive, and smooth. This is already a goal of a good SEO strategy.

  • LCP is one way to measure that webpages load fast. It helps your website visitors have a good user experience and stay on your site.
  • FID plays into another good SEO strategy, to keep visitors on your site.
  • CLS helps ensure that the experience is smooth for your mobile users, a key SEO strategy.

Google has not yet specified the percentage of rankings the new page experience signal impacts. We also haven’t heard exactly how core web vitals play into the overall page experience ranking update either. But we do know that earning “good” scores can help your rankings. According to John Mueller, page experience “is a ranking factor, and it’s more than a tie-breaker, but it also doesn’t replace relevance.”

Search Engine Land spoke to a Google rep and reported that Google would not discuss “how much each factor is weighted” but that “great content with a poor page experience can still rank highly in Google search.”

Perhaps a different view will help: If your site is slow, it cannot respond quickly to a voice search request. Will voice search become increasingly important? Of course. So overall speed is vital going forward.

It’s also suspected that Google’s AI, RankBrain, takes into account how users engage with the search results. RankBrain’s goal is to interpret search queries better and serve the most relevant search results. Specifically, RankBrain may look at the time spent engaging with a webpage when accessed from the search results.

Keep in mind that a fast site finds favor in Google’s eyes. It creates a better user experience, and that’s good for all. For that reason, page speed has been a ranking factor for years. The most recent news on this was the “speed update” for mobile that rolled out in 2018. The page experience update makes that more granular, with many metrics being tracked.

Core web vitals help ensure users are happy and stay on your site. This, in turn, can impact rankings. See an earlier article I wrote on SEO and the user experience.

Core Web Vitals and the ‘Fast Page’ Label

Is your website ready to pass the thresholds for core web vitals? If not, you’re not alone.

According to research by Screaming Frog published in August 2020, only 12% of mobile and 13% of desktop results passed the assessment.

A more recent study by Searchmetrics found even worse results. Less than 4% of the two million URLs they checked could pass all of the core web vitals tests!

It’s likely that Google knows the work that is ahead of website publishers, which explains why the search engine announced it a year in advance. Google also announced an added incentive: a “fast page” label that would be added to search results on Chrome for Android, starting in Chrome 85 Beta.

How can you earn that label for your webpages? Google says that “links to pages that have historically met or exceeded all metrics thresholds for the core web vitals” get the label.

(While Google says “all” core web vitals, it’s unclear how cumulative layout shift factors into the fast page label.)

Google example of the "fast page" label in SERP.

That means that even though Google said back in May 2020 that “there is no immediate need to take action,” it tried to make core web vitals a little more enticing to get a head start on.

That’s because sites with a “fast page” label in the results can potentially garner more clicks. This is reminiscent of the “mobile-friendly” labels Google created back in 2014, when it wanted website publishers to start putting mobile users first.

More on Core Web Vitals

As we continue our series on core web vitals, I’ll highlight each of the factors — LCP, FIC, and CLS — and include frequently asked questions on how to prepare for the coming page experience update.

You can find out about each page experience factor in our series:

  1. What’s the Page Experience Update?
  2. How to Make a Mobile-Friendly Site
  3. Intrusive Interstitials & Why They’re Bad for SEO
  4. HTTPS for Users and Ranking
  5. Core Web Vitals Overview
  6. Core Web Vitals: LCP (Largest Contentful Paint)
  7. Core Web Vitals: FID (First Input Delay)
  8. Core Web Vitals: CLS (Cumulative Layout Shift)
E-book on the Page Experience Update.
Click to get this entire series as a printable e-book.

Would you like help analyzing and improving your SEO strategy? Contact us for a free consultation today.

FAQ: How do Core Web Vitals contribute to a better user experience and SEO?

User experience and search engine optimization (SEO) are pillars of online success. The nexus between these two lies in Core Web Vitals – crucial performance indicators that encapsulate the essence of a website’s responsiveness, speed, and stability.

Core Web Vitals represent a set of performance metrics Google has identified as integral to a seamless user experience. Comprising Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS), these metrics gauge a webpage’s load time, interactivity, and visual stability, respectively. By scrutinizing these aspects, search engines evaluate how effectively a site engages and retains visitors. A website that responds swiftly, allows quick interactions, and prevents unexpected layout shifts resonates more positively with users, thereby improving its SEO prospects.

User experience has become an increasingly pivotal factor for both users and search engines. In its pursuit of delivering the best results, Google factors in Core Web Vitals when determining the ranking of a webpage. A site that offers a smooth and expedient experience is more likely to receive favorable treatment in search engine results pages. Consequently, optimizing Core Web Vitals can yield a double benefit: it satisfies users by providing a better interface and enhances a site’s visibility in search results.

To grasp the impact of Core Web Vitals on user experience, consider their influence on page speed. The Largest Contentful Paint, measuring the time it takes for the largest element to load, directly affects how quickly users perceive a site as ready for interaction. Pages that load swiftly captivate and retain users’ attention, reducing bounce rates and contributing to longer dwell times – factors that search engines appreciate. This underscores the symbiotic relationship between user engagement and SEO.

One insightful tip for optimizing Core Web Vitals is to focus on efficient content delivery. Employ content delivery networks (CDNs) to distribute assets across multiple servers, ensuring users receive resources from the server closest to them. This technique minimizes latency, accelerating load times and positively impacting LCP. By prioritizing resource loading and leveraging browser caching, webmasters can significantly enhance both user experience and SEO performance.

Core Web Vitals are pivotal in shaping a website’s user experience and influencing its SEO rankings. Prioritizing these performance metrics isn’t just about meeting search engine requirements – it’s about delivering a website that resonates with users and keeps them engaged. By optimizing Core Web Vitals and focusing on strategies to enhance webpage performance, businesses and website owners can establish a strong online presence and foster better user interactions.

Step-by-Step Procedure: Optimizing Core Web Vitals for User Experience and SEO

  1. Assess current Core Web Vitals metrics using Google’s PageSpeed Insights or other relevant tools.
  2. Identify the web pages with suboptimal performance metrics.
  3. Prioritize content delivery by utilizing content delivery networks (CDNs) for efficient asset distribution.
  4. Implement lazy loading for images and videos to load resources only when needed, improving LCP.
  5. Optimize server response times by utilizing caching mechanisms and minimizing server-side processing.
  6. Minimize JavaScript execution time to enhance FID by removing unnecessary scripts and optimizing critical scripts.
  7. Prioritize above-the-fold content to ensure faster rendering and improved user engagement.
  8. Optimize CSS delivery by minimizing render-blocking resources and utilizing asynchronous loading techniques.
  9. Address layout shifts by setting explicit dimensions for media elements and utilizing CSS properties.
  10. Monitor Core Web Vitals regularly and track improvements over time.
  11. Utilize browser caching effectively by specifying appropriate cache durations for different types of resources.
  12. Optimize images and other media assets by compressing them without compromising quality.
  13. Implement code minification and bundling to reduce the size of HTML, CSS, and JavaScript files.
  14. Leverage browser preloading to anticipate user actions and preload essential resources.
  15. Implement responsive design to ensure smooth rendering across various devices and screen sizes.
  16. When optimizing and testing third-party components and scripts to avoid performance bottlenecks.
  17. Take advantage of modern web technologies, like HTTP/2 and HTTP/3, for improved server-client communications.
  18. Continuously monitor server performance and uptime to prevent disruptions in Core Web Vitals metrics.
  19. Conduct A/B testing to evaluate the impact of optimizations on user experience and engagement.
  20. Stay updated with industry trends and Google’s guidelines to adapt and optimize Core Web Vitals accordingly.

Bruce Clay is founder and president of Bruce Clay Inc., a global digital marketing firm providing search engine optimization, pay-per-click, social media marketing, SEO-friendly web architecture, and SEO tools and education. Connect with him on LinkedIn or through the website.

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7 Replies to “Core Web Vitals for SEO: An Overview”

The article is extremely helpful for me. I learned very useful information about keyword research from this post. Article is nicely explained and easy to understand. Thanks for sharing this valuable information with us.

You have shared some very insightful information about the core web vitals. But when I check it in my search console it says that there is not much data yet especially for mobile.

Thanks for covering all the concepts in one blog. We’ll look after these LCP, FID, CLS points in our future projects as it’s vital for 2021. I also forwarded your blog to our department so they can also read & start their work accordingly.

Paula Allen

PSG Grant: We hope the information and all the linked sources provide all you need to improve your website UX. Thanks for reading and letting us know.

After this Google update, It gives priority to websites which have been designed user friendly.

Very informative stuff, so 2021 is going to be an year of web vitals. Let see how it goes!!

Very interesting information in here. I always appreciate industry updates, and will certainly begin implementing changes to adapt to newer standards. I am very curious to see how much of a weighting Google places on this aspect going forward in their ranking methodology.


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