Google Core Web Vitals: What Are They & Why Do They Matter?

Reports showing a website’s performance

To help developers improve websites, Google has come up with a set of standardised metrics called Core Web Vitals. Although these metrics are primarily created for developers, all site owners can use them as they help gain insight into how users experience the web page in the real world.

Core Web Vitals focus on three specific areas for measurements, including site speed performance, visual stability from a user’s perspective, and ease of interaction. Ideally, developers need to use a holistic approach when considering user experience, and these three metrics break down all variables into smaller, more manageable pieces to assist site owners. Each metric provides a perspective on elements that impact user engagement and interactions. As a result, developers and site owners can identify areas of improvement and fix technical issues throughout the site.

While these metrics don’t paint a comprehensive picture of the user experience, they can be pieced together to understand your target audience’s perspective and troubleshoot issues efficiently. We asked our web development experts in Canberra to define Google Core Web Vitals in detail to help you understand their importance for your website. Here’s what they have to say.

Largest Contentful Paint (LCP)

The first Core Web Vitals metric is Largest Contentful Paint or LCP focusing on the site speed (the time it takes for your page to load). It evaluates the render time of the largest blocks on your website visible to the users to tell whether they find the site useful or not.

In today’s fast-paced era, everyone requires instant results, so your site must load fast and ensure a pleasant user experience. A web page that loads fast provides a positive user experience and has more chances of ranking higher on Google SERP. Faster site speed also improves the conversion and engagement rates of your website.

How LCP Works

A website consists of different content blocks like block-level text, images, background images, and video poster images. LCP metric measures the time it takes for each content block to load on the user’s current screen. This screen could be a desktop or mobile device.

LCP only tells you how quickly these blocks render on the visible screen, not the elements that are below the fold. Ideally, a website should complete loading all content blocks within 2.5 seconds (or less) for 75% of visitors (or more).

 A person is analysing data

Cumulative Layout Shift (CLS)

The second metric in Google Core Web Vitals is Cumulative Layout Shift (CLS) that focuses on ease of interaction. It identifies buttons and links that shift once the website is fully rendered on the user’s screen. This tells site owners the level of difficulty/ease users face when trying to interact with elements on a site.

As a site owner or developer, you need to make it as easy as possible for your users to engage with buttons and links on your website. This directly affects your sales and conversions.

Design and UX are crucial elements of a pleasant user experience. If a web page shifts elements while a user is viewing its contents, it can result in frustration and a higher bounce rate. With CLS, you can identify if links or visual content on your web page is shifting so you can improve usability for higher CTRs and online sales.

Working of CLS

Sometimes when a user opens a website, elements like buttons or links shift from their original position to another, preventing them from interacting (or completing an action). CLS measures the shift of elements between two rendered frames. So if your website pushes banners, text, or buttons while a user is exploring content on their screen, CLS will let you know.

The shift of elements confuses the users and affects their experience. Therefore, ensuring their consistent position is important for site owners. CLS considers factors like Layout shift, distance fraction and impact fraction for measuring the shift of elements. You should aim for a CLS of 0.1 or less to provide a good user experience.

 A person is exploring images on a website

First Input Delay (FID)

To improve the appeal and visuals of a website, developers and designers incorporate various widgets and content elements. While these elements make a website look appealing to users, they may cause delayed responses, making a user wait for a long time.

First Input Delay or FID is the third core web vital that measures the time it takes the elements on your page to respond to users. People want websites that load in a snap and provide quick engagement responses. With FID, you can determine the input latency of your website to eliminate unnecessary delay resulting in user frustration. By reducing the response time, you can improve your website’s usability and engagement rate.

When a user makes an input request, FID measures the time it takes for your page to respond. It records events like key presses and clicks. For an ideal experience, you should maintain FID below 100 milliseconds. Out of all Core Web Vitals, maintaining a good FID score is the trickiest because it only measures the user’s input in the field. The score depends on factors out of your control, such as the user’s internet speed or device capability

Other Performance Metrics to Consider

Besides Core Web Vitals, there are some other performance metrics that Google evaluates to identify elements affecting user experience. These metrics include:

  • First Contentful Paint (FCP):It tells how long it takes for users to view DOM elements on their screen. DOM elements include images, SVGs and non-white elements.
  • Speed Index:SI tells how long it takes for your site to display to a user and is measured in milliseconds. A website with 0–4.3 seconds SI is considered fast.
  • Time to Interactive:TTI considers the time for the page’s content to be fully interactive and functional. 0–3.8 seconds or TTI is considered ideal.
  • Total Blocking Time:TBT identifies web pages with unnecessary JavaScript to tell how long your web page takes to respond to user input. It should be under 300–600 ms.
  • Page Performance Score: It’s a unique metric that factors in all essential user experience metrics to provide an aggregate score. Knowing this score helps you understand the overall experience of your website on all kinds of website visits (mobile or desktop). A score of 90 is considered good and below 50 is poor.

Website development in process

We hope this blog has provided you with valuable information regarding Google Core Web Vitals. To read more helpful guides, explore our blogs here.

TocToc is the leading digital marketing company in Canberra, Australia, led by Ben Fullarton, an experienced SEO expert. We provide all kinds of online marketing solutions, including email marketing, content marketing, web design and development, and SEO. Contact us to get started.




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