[Core Web Vitals] What they are and how they can help you improve your eCommerce positioning


It is no secret that Google rewards websites that offer good user experience.

The issue is how it’s measured.

How can you evaluate a matter that is affected by so many factors and criteria?

So far, it has been done by checking different KPIs. However, Google has now decided to unify their metrics to define user experience as the combination of loading speed and usability. That’s how Core Web Vitals emerge.

Think about them as “the main web metrics” for controlling UX.

There are 3 basic aspects to them:

  • How fast the website loads.
  • How fast the user can interact with the website.
  • How stable the website is while it loads and the user interacts with it.

In this post we’ll explain in depth what each of these metrics consists in, where to find them and how you can use these data to improve the UX in your e-commerce.

So keep on reading; you’ll find this interesting. 😉

👉 What Core Web Vitals are and why you need to keep them in mind for your online store’s SEO

Let’s start with a definition.

Core Web Vitals, or “the main metrics of a website”, are Google’s new metrics that tackle different aspects of user experience.

Thanks to Core Web Vital values, we can know if our e-commerce user experience is good or if, on the other hand, we must improve it.

In case you don’t know, user experience or UX is the way (positive or negative) in which a user perceives our website when interacting with it.

Whether the experience is positive or negative depends on many factors. Amongst them, there’s web usability and loading speed, which are precisely what Web Vitals measure.

But what benefit do these new metrics offer?

So far, we’ve had to control many different tools and metrics to analyze user experience. The purpose of Core Web Vitals is to simplify this process and to unify everything that relates to UX in a single and user-friendly metric.

✅ Why it’s relevant that you know Core Web Vitals

As you know, Google takes into account many factors for positioning a website. Without a doubt, one of the most important ones is user experience on the website.

Core Web Vitals are designed to help you measure user experience, which is why it’s logical that Google keeps this metric in mind in order to rate a website either positively or negatively.

In fact, as announced on a post by Google Search Central: Core Web Vitals are some of the indicators Google will be using for positioning. Ultimately, the search engine’s goal is to provide the user with websites that offer high-quality content as well as a comfortable and easy browsing experience.

Here’s a thorough video about how these indicators affect your website’s SEO. If you can, make some time to watch this:

👉 The 3 metrics used by Core Web Vitals to measure user experience

Although it’s been said that these metrics will change in time, there are currently 3 key aspects for measuring user experience: LCP, FID and CLS.

Possibly the acronyms don’t mean much on their own. Let’s see what each of them is about!

✅ 1. Main content loading speed (LCP or Largest Contentful Paint)

It measures the web’s contents loading speed in a pretty particular way.

We can think of it as the first “test” the website needs to pass when a user visits it. If the first thing they see is a white screen with a loading icon, they get nothing out of it. That’s why LCP doesn’t measure how long it takes for the website to load but for the most relevant content for the user to do so.

In other words, it measures how quickly the main content of your store shows up.

This could be, for example, a large image, a video or text, and it’s usually located above the fold —the upper part of the site that’s visible without having to scroll down.

Now, what values does Google establish to evaluate your LCP?

For it to be considered good, loading speed must be below 2.5 seconds.


✅ 2. Interactivity (FID or First Input Delay)

The user has visited your store’s web. So far so good. But after browsing the homepage, they click on one of the categories and the site takes more than it should to process this action.

This metric does precisely this: it measures the speed at which a website responds to user interaction.

In the previous example, it would measure the lapse between the moment the user clicks on the category button and the site’s response to that click when it starts loading the next page. In other words, it’s the time that elapses until the moment the button becomes “clickable”. If the button takes its time to work, user experience will be in turn affected.

According to Web Vitals, for the FID to be good, it must be below 0.1 seconds.


3. Visual stability (CLS or Cumulative Layout Shift)

Surely, it’s happened to you that you want to click on a button or an image, but right when you’re about to do so, it moves and you end up clicking on another button that takes you to a site you didn’t mean to visit.

Why does this happen?

As a website’s elements load and they find their place, they displace the ones that had already loaded. If this doesn’t happen fast, user experience ends up being affected.

That’s what this metric is for.

What we want to find out here is whether your store loads smoothly or whether it buffers, making the elements change place as they load.

The more they move around, the higher the score will be on the visual stability metric, and the worse the evaluation will be.

In order for user experience to be considered good, the CLS score should be lower than 0.1


👉 How can we know our Core Web Vitals?

You already know what they are about. Let’s see how to get them.

✅ 1. Google Search Console

Log into your Google Search Console account and look up “main web metrics” on the main menu.

Everything you need is there, both for mobile and desktop versions.

Does it display no info?

This may be because you still don’t have enough information on your Chrome user experience report —or Chrome UX report. This report done by Google gets real user-experience metrics for different URLs and then transfers them under this section. If your site does not have enough traffic or your Search Console account is rather recent, the report will most likely not be available yet since there’s not enough data for it.

If this isn’t your case, you should be fine for getting your Core Web Vitals.

✅ 2. Google PageSpeed Insights

It’s another tool developed by Google that provides us with every single metric about a site’s loading speed. In order to do that, it uses:

  • Field data: based on info from real users. These data are collected by the above mentioned Chrome UX Report.
  • Lab Data: experiment-based estimations conducted by Lighthouse (another tool developed by Google) that uses lab data to provide you with info about different aspects of your website to be improved.

In order to get these data, you simply need to go on PageSpeed Insights and type in your website’s URL.

As you can see, this tool shows us both LCP and CLS.


However, just like before, we don’t always get FID data.

This is because of what we’ve mentioned before; in order to get that metric, you need field data. If Chrome UX Report does not have enough information, it won’t be able to provide us with this metric.

Last, one of PageSpeed Insight’s interesting contributions is it generates a score for your website’s performance, and tips as to how to improve it.


👉 Final tips to improve your score

Once you know your score, the same tool will give you some suggestions that may come in handy to fix speed problems.

However, here are some basic tips so you can improve your website’s speed:

  • Optimize images: avoid images bigger than 150 KB and always adjust sizes to the dimensions they will actually be displayed at on the web. If, for example, they are displayed at 300×300 pixels, it wouldn’t make sense for you to upload them at 600×600, taking up more space than needed.
  • Avoid an excess of plug-ins: even if extensions are useful for adding functionalities to your website, try to include only those you really need, since too many active plug-ins would slow down the website’s performance.
  • Get a quality hosting: even if you’re spending a bit more, you should pick the right hosting if you want your website to be fast.

In addition, Google has made guides to improve website speed available for users. However, these tend to be a bit more complex and, in many cases, you need to have some code knowledge. 

✅ BONUS: How to optimize Core Web Vitals for your e-commerce

Last, here’s this video made by Google that explains how to improve Core Web Vitals in a very entertaining way.

👉 Let Core Web Vitals guide you in improving UX

Are you now familiar with these new metrics?

Make the best of them to go beyond and keep on improving your store’s user experience in every aspect.

Good user experience will not only make Google “like” your store or position it better; it will also become vital for your customers to feel at ease in your store.

So don’t lag behind! As we always say: keep on measuring! 😉