What are Core Web Vitals?

It’s important to know what Core Web Vitals (CWV) are, why they’re important, and how they’re measured. By improving your understanding of CWV and optimising your website, you’ll increase traffic and further your business. So, let’s get into it.

What are Core Web Vitals, and why are they important?

CWV are a set of metrics that Google uses to evaluate your website’s performance and user experience. With CWV, Google’s primary goal is to improve the web by increasing website building standards.

A high CWV score creates a seamless user experience for your visitors. This includes quick loading times, ease of interaction, and simplicity of navigation. A positive user experience means visitors are more likely to convert or return to your website.

When did Core Web Vitals start?

Google introduced Core Web Vitals in May 2020. It is one of the biggest shakeups in years, affecting how businesses build and maintain their websites.

Do core Web Vitals affect SEO?

Yes! A good Core Web Vitals score ensures you rank highly on Google, increasing the likelihood of your website appearing on the first page of results. It adds authority to your site and increases the number of visitors.

How is Core Web Vitals measured?

Google look at three principal quality tests for a CWV score:


Largest Content Paint (LCP) – This looks at the main content’s loading speed. LCP should be 2.5 seconds or quicker.


First Input Delay (FID) – FID inspects how quickly a user’s browser begins processing an action when they interact with the page. This could be the speed the browser starts to process the action after the user has clicked on a link. A page’s FID should be 100 milliseconds or less.


Cumulative Layout Shift (CLS) – CLS measures the visual stability of a webpage. For example, do certain elements such as banners or images unexpectedly shift? This is especially common on mobile. A page with a CLS of 0.1 or lower will provide a good user experience.

How to perform a Core Web Vitals test

If you’re wondering how to pass core web vitals, don’t worry. Quality tests can be easily measured using several Google tools such as:

How to improve Core Web Vitals

There are several core web vitals updates that will improve website score:

  • Server Speed – A fast server is vital for good site speed. After all, a Ferrari won’t drive fast on a dirt track!
  • Improve Largest Content Paint (LCP) – Identify the largest item which loads above the fold. This can be moved down or made small if it’s an image. For a large text block, simply split it into paragraphs
  • Improve First Input Delay (FID) – Caching can sometimes help with this. However, optimising your JavaScript code will have the biggest impact.
  • Improve Cumulative Layout Shift (CLS) – Set width and height size attributes to all image and video elements.
  • Eliminate render blocking elements – Slow loading elements will stop other important elements from loading.
  • Optimise images – Image file sizes should be kept as small as possible without sacrificing on quality. It’s also important to have the correct image size for each device.

At Union 10, we are well-versed in all things CWV. Get in touch today to see how we can take your website to the next level.

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