Google Core Web Vitals are a set of three specific metrics which Google considers very important in the loading of any page on the web.
Google is rolling out Core Web Vitals measurement across the web in the second half of 2021.
It is believed that a website’s ranking in Google search results will be affected by it’s performance versus Google’s Core Web Vitals metrics.
Google is commited to helping site visitors have a better experience when visiting web pages.
Please note that I say ‘web pages’ and not ‘websites’. The reason for the distinction is that the page a searcher has clicked through to might be one of your internal pages rather than your homepage. Chances are this is a high ranking page and it may even be your ‘money page’. The one that is driving many of your sales or warm leads.
Web pages which are slow to load and respond to user interaction create a negative experience for a site visitor. Your site visitors should be able to quickly view, understand and then engage with your website in a meaningful way.
The 3 Core Web Vitals Metrics
The three different metrics in Google Core Web Vitals are as follows;-
Largest Contentful Paint (LCP)
LCP measures how long your web page takes to load from the perspective of an actual user.
What this means in reality is Google are measuring the load time of the web page’s content above the fold (think of before the fold as top section of a folded newspaper on a newsstand with the banner and the headline on it) rather than the entire web page.
Largest Contentful Paint is primarily concerned with what really matters to your site visitor when they click through i.e. how long it takes to view and interact with the page’s content.
Google’s metric requires that LCP should occur within 2.5 seconds of the moment the page first starts to load.
Factors that will effect LCP include the response time of your web host’s server, render blocking scripts (these are scripts that stop the content being shown on the screen until they have loaded), size and complexity of the website’s stylesheet, loading of external fonts, and the file size of any images that must be loaded.
Placing an autorun video at the top of the page is suicidal for LCP.
First Input Delay (FID)
First Input Delay measures the time to user interactivity on your web page or the time it takes for a user to actually be able to first interact with the content on your page.
This might include actions such as clicking a button or a link in the menu, entering data into a form or interacting with content such as accordions or interactive maps etc etc…
FID goes beyond the visual, measuring the time it takes for users to be able to perform an action on your page.
To meet Google’s preferred metric, your web pages should return a FID of 100 milliseconds or less.
Cumulative Layout Shift (CLS)
Ever loaded a web page where the page is loading and you are about to click a link and then the link jumps down and you click completely something else? I hate that!
Well, it turns out Google doesn’t like it either.
CLS is a Google metric that measures how visually stable the above the fold content is on a page as it loads.
Google’s metric suggests a CLS of less than 100 milliseconds.
What Happens if a Web Page’s Core Web Vitals Do Not Meet Google’s Metrics?
As with many things Google does in the world of SEO, the effect of not hitting their recommended targets is not clear and defined.
Unusually though, Google has said that poor Core Web Vitals metrics can result in poorer rankings.
Understanding what Google is consistently trying to achieve in the area of improving the user experience on the web would suggest that Core Web Vitals will have a marked effect on your web page’s rankings so it is certainly worth checking out and fixing.
If your competitors are meeting the metrics and your site isn’t then they have a decided advantage on you all other things being equal.
How Do We Test Our Web Page Core Web Vitals Performance?
There are quite a few free (and more paid) ways to check out how your web pages perform versus Core Web Vitals.
The Google Page Speed Insights utility is a great resource that will not only allow you to test your pages, however, will give you detailed results and recommendations as to the issues.
The Web Page Test utility is also a great resource for Core Web Vitals testing.
If you have a free Google Search Console account then this can give you detail as to how multiple pages on your website are performing historically.
Additional Reading on Core Web Vitals
If you are looking to go to the next level of knowledge and testing on Google Core Web Vitals then we recommend this page by Backlinko which offers a very informative (but readable) summation.