A guide to Google’s Core Web Vitals

18 Dec 2020

SEO

Nick Boyle

Nick Boyle

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As an avid follower of Google, we’re always on the lookout for any changes and upcoming announcements. Whether it’s Froogle coming back or their switch to mobile-first indexing – we’re on it. 

And we’re here to tell you about another exciting Google update. 

Back in May 2020, Google announced that page experience signals would be included in Google Search ranking. 

When will the page experience update roll out?

Google first announced the launch of the update would be in May 2021. But, now because of a slight delay, the gradual rollout will start mid-June of 2021 instead. Google says:

“We’ll begin using page experience as part of our ranking systems beginning in mid-June 2021. However, page experience won’t play its full role as part of those systems until the end of August.”

In anticipation of the big day, let’s break it down and remind ourselves why Core Web Vitals are, well, vital!


Google Core Web Vitals page experience update – April and March 2021

April: The latest update on the update can be found in their GSC Blog. What’s new?

  • Delayed gradual rollout to start in mid-June 2021
  • On 19 April 2021, they announced “the general availability of signed exchanges (SXG) on Google Search for all web pages. Google Search previously only supported SXG built with the AMP framework.”
  • They’re expanding the usage of non-AMP content to power the core experience on news.google.com and in the Google News mobile apps
  • A new Page Experience report in Search Console. Google says this will “provide you with more actionable insights [and] combines the existing Core Web Vitals report with other components of the page experience signals, such as HTTPS security, absence of intrusive interstitials, safe browsing status, and mobile friendliness.”

    It looks something like this:

Page experience report in Search Console example

March: In March 2021, Google greeted us with their Core Web Vitals & Page Experience FAQs forum, here was the 411:

Where does the page experience data come from for Google to consider?

Google will use their Chrome User Experience Report and field data to analyse user visits and interactions with web pages, specifically humans, not the bots.

What determines a pass or a fail for a web page in page experience ranking?

By using metrics that are calculated at the 75th percentile over a 28-day window, Google can work out that most visits to a site (3 of 4) experienced “the target level of performance or better.  If a page hits the recommended targets for all three metrics, it passes the web vitals assessment.”

How important is this page experience update compared to other ranking signals?

Think of it as another factor, another signal on top of what you should already be doing to help your SEO and rankability. Google’s search algorithms already use hundreds of signals to determine ranking and appropriate content to search queries; the user or page experience is an additional one. With all these signals to consider, Google will still prioritise “pages with the best information overall, even if some aspects of page experience are subpar. A good page experience doesn’t override having great, relevant content.” So, basically, maintain high-quality content, but don’t let your site put off visitors or annoy them, as Google will also be annoyed – they don’t want to show poor sites now do they, and they’re taking that seriously.

Will Core Web Vitals be a ranking factor when using Google on non-Chrome browsers?

Google says yep, no matter the browser, page experience signals – based on Core Web Vitals – will be applied globally on all browsers on mobile devices.

Will sites be eligible for Top Stories carousel, even if they don’t clear Core Web Vitals?

Excitingly, with Google’s upcoming change to Top stories carousel, they say that “all web pages irrespective of their page experience status or Core Web Vitals score are eligible for Top Stories carousel. When the changes go live, the compliance with Google News content policies will be the only requirement.

Google's Top Stories carousel example for search query 'suez canal'
Google’s Top Stories carousel example for search query ‘Suez Canal’


What are Google’s Core Web Vitals?

Let’s throw this handy diagram at you to help understand Google Search signals a bit better. 

Google's Core Web Vitals diagram showing loading, interactivity and visual stability affect search signals for page experience.

As you can see, there are three Core Web Vitals that Google place as a priority over others in helping a website rank.

Google's Core Web Vitals measurement for websites, showing LCP, FID and CLS.

Also see Google’s Core Web Vitals report that goes more into the LCP, FID and CLS measurements on your site’s performance, and how to fix poor user experiences.

1. Why loading is a Core Web Vital

Largest Contentful Paint (LCP) – measures how long it takes for a page’s main content to load. You’re looking for around 2.5 seconds or faster for a good LCP

How many times have you clicked on a website, only to be left twiddling your thumbs and rolling your eyes because of its load time? Not only can this leave us disappointed and clicking the back button, but Google’s crawlers and bots pick up on it too, and it all affects SEO (and even more so come May 2021). Just take a look at how Google and its robots measure a site’s technical SEO with accessibility and crawlability.

Businesses are always looking for ways to grab your attention; it could be a fancy pop-up, a discount code ad or newsletter sign-up banner. But if there’s too much going on in the code, the load time is going to be impacted, and the bounce rate will skyrocket in response. Not to mention it’s downright annoying for the customer.


That’s why webpage load time is in the top three core web vitals for Google. Get this right, and you’re in with a higher chance of the search engine favouring your website over others. The extra seconds you leave users waiting could be the reason you may end up on page 2.

2. Why interactivity is a Core Web Vital

First Input Delay (FID) – how long it takes for a web page to become interactive. Google’s ideal time is less than 100ms

This core web vital is focused on the time it takes for pages and their content to become interactive or responsive. 

So, your site may look shiny and appealing – and it may even run well – but if your site’s interactive elements are slow to load, Google’s not going to appreciate it. 

Think about it, you want to impress your users, and so does Google. Any searcher that comes to Google is expecting the best results, and so it was inevitable that Google would start to take interactivity and responsiveness into account in its ranking signals. 

3. Why visual stability is a Core Web Vital

Cumulative Layout Shift (CLS) – measures how much of a page’s visual layout and content shifts unexpectedly. Ideally, you want no more than 0.1

This third top core web vital is just a fancy way of saying how stable your site’s layout is. 

What Google looks out for here is how much a page’s layout may shift (how stable it is) during load time. So, if elements are moving around quite a bit as the page loads, the CLS is going to be high, which is not good. 

Issues that arise with a high CLS can mean links shifting around, so when a user spots a handy link they want to go to, they may end up clicking something else. Very annoying – bet it’s happened to you, hasn’t it?

Google’s UX signals

It’s important to remember that whilst LCP, FID and CLS will become ranking signals (and perhaps new boy bands) for next May, Google will combine these with the existing UX signals also, so don’t forget about:

How will Google use Core Web Vitals in its search engine results, then?

Currently, when searching on Google, you’ll often see either organic (SEO) or paid (PPC) results.

You’ll sometimes get a featured snippet right at the top, or may see a bunch of useful related questions with snippeted answers from different sites. 

Google search engine result page showing a featured snippet for the query 'what is a featured snippet'

So if you can get your site a snippet here, it means you’ve done a pretty good job of answering a search query.

Now though, Google will not only want to put the most useful and relevant content in front of searchers, but they also want to make sure potential website visitors and users have the best user experience. So then, it makes sense that they are going to signpost this in their SERPs going forward.


Upon successful testing, come May 2021, you can expect to see visual indicators on results pages that will identify pages that meet all of the page experience criteria. More details on this are to be announced in the coming months, Google says.

How to improve Core Web Vitals: what does Google recommend?

Use of AMP (Accelerated Mobile Pages) content

Along with this ranking signal update, Google has also stated that:

“The change for non-AMP content to become eligible to appear in the mobile Top Stories feature in Search will also roll out in May 2021.”

They also say that any page that meets the Google News content policies will be eligible and that they will prioritise pages with “great page experience, whether implemented using AMP or any other web technology, as [they] rank the results.”

But, for AMP, Google stresses that it’s one of the most cost-effective and easiest ways to help publishers improve their page experience outcomes. 

“Based on the analysis that the AMP team has done, the majority of the AMP pages achieve great page experiences. If you’re an AMP publisher, check out the recently launched AMP Page Experience Guide, a diagnostic tool that provides developers with actionable advice.”

As well as this, to be ready for the changes next year and to help your site meet the page experience criteria, Google has a few more resources for you to use:

Want to be all set for Google’s new visual page experience indicator? Speak to our technical SEO experts to see how we can help your site be ready. Get in touch today.

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