In this piece we’ll be talking about Google’s latest announcement that page experience will become part of its ranking algorithm next year, further blurring the line of separation between SEO and UX.

It has identified several key webpage elements that affect users and impact their experience on a website – grouping them under the term ‘core web vitals’.

So what are Core Web Vitals?

Core web vitals are metrics that identify whether a webpage delivers a good overall experience for users. The main indicators are:

  • Largest Contentful Paint (LCP)
  • First Input Delay (FID)
  • Cumulative Layout Shift (CLS)

What is Largest Contentful Paint?

Largest Contentful Paint refers to loading times of a webpage through the user’s interface. In order to provide a good experience, websites should load the main content of the webpage within 2.5 seconds. If it takes longer than this to render, Google considers this a poor user experience.

What is First Input Delay?

FID relates to the lag between a user’s request i.e. opening a page, and the website’s response. This should be less than 100 milliseconds in order to provide a good experience.

What is Cumulative Layout Shift?

CLS measures the movement of elements on the page when the page is loading and aims to combat content jumping as a page renders in the browser. A good score is below 0.1 – which is generated from a number of calculations.

How can I measure Core Web Vitals?

You can measure the Core Web Vitals of your own web pages using the following tools:

  • Search Console
  • PageSpeed Insights
  • Lighthouse
  • Chrome DevTools
  • Chrome UX Report
  • Web Vitals Extension

How can I improve Core Web Vitals?

With the help of a developer, there are a number of changes that you can make to improve these scores and thus, improve the experience for users.

Core Web Vitals are often influenced by some of the following factors:

  • Size of assets needed to render
  • Number of requests a page needs to load
  • Server speed
  • Type of resources being loaded
  • Your web platform

But before deciding you’re going to need a brand new website, maybe look at the following fixes:

  • Optimise critical rendering: Reduce the number of critical resources needed to render the page. If they can’t be removed, try running them asynchronously.
  • Lazy Loading: Load visible, above the fold images first, then load others when needed. There are extensions available to help with this.
  • Enable browser caching: Cached resources mean that once a resource has been downloaded, the browser doesn’t need to make additional requests to the server to get it again.
  • Use a CDN: Short for content delivery network, a CDN caches your website data in numerous data centres, so that it can be delivered from somewhere closer to where the user is accessing it from.

Improving core web vitals won’t be a quick fix – which is part of the reason Google has given website owners at least 6 months before they start rolling it out as a ranking factor in their core algorithm.

But by starting to make changes now, your website will not only benefit from the long term search engine changes, but it will be more user friendly for customers on your website. Having a modern (often mobile) experience will help show new visitors that your site can be trusted and is easy to use.

For help improving your website’s core web vitals, or any other eCommerce project you have, feel free to contact one of our consultants to find out more at

Alex Gregory

Senior Ecommerce Consultant