How To Audit Web Core Vitals

So if you’re looking to improve your SEO in 2021, here we discuss Web Core Vitals, what they are, how to check them and how to improve them.

Core Web Vitals: What You Need to Know

Core Web Vitals are a set of real-world metrics Google will use (from May 2021) to measure key aspects of user experience when loading a webpage.

In addition to being small signals for Googles scoring, they’re also exploring labelling search results with symbols to indicate pages with good or bad CWV scores.

Initially the three metrics Google will use are:

Largest Contentful Paint

Largest Contentful paint (LCP) is a measure of the overall loading speed of a page – the faster the page loads the better. It’s marked in the timeline when the majority of content is loaded in.

First Input Delay

The First Input Delay (FID) of a page measures its responsiveness to user interactions. For instance, if a user clicks a link, or selects a dropdown – how quickly will that action be executed on the page. Usually, user interactions will be delayed when a browser is busy executing other tasks

Cumulative Layout Shift

The Cumulative Layout Shift (CLS) of a page measures the stability of a URL as it loads. We’ve all had that frustrating experience of reading a news site and having the article text jump lower as the navigation is loaded, and CLS is a measure of that across a whole page.

Core Web Vitals Assessment

As mentioned Core Web Vitals are based on real-world user metrics. This data is supplied by the Chrome User Experience Report (CrUX). Though it is possible to use simulated lab data to gauge performance when real user data is unavailable. This CrUX data is based on the last 28 days of user visits to a page.

Initially, these Web vitals will only become part of Googles algorithm on mobile pages, though desktop may also be introduced later.

How to View a Pages Core Web Vitals

Your sites Core Web Vitals are recorded and stored within the Chrome User Experience Report, there are various APIs to connect with this, but you can most commonly see them in two places.

For an individual URL you can use PageSpeed Insights (PSI), which marks each Web Vitals with a blue flag, and whether or not the page has passed the Core Web Vitals assessment.

Alternatively, you can see a sample of pages within Google Search Console (GSC), which will show performance over time.

How To Improve Your Core Web Vital Scores

To be clear, the exact steps you take to improve your core web vitals depends on your site.

For example, a site that runs on Shopify will be different compared to one that runs on WordPress.

That said, here’s the process you can use to figure out what you need to fix.

First, pop open the Google Search Console and click on “Core Web Vitals”.

Basically ignore the desktop scores. Google’s mobile-first index means that mobile scores are what really matter.

You want to really zero-in on “poor URLs” and for our Core Web Vitals are looking good.

There are various areas you can examine to improve your web vital performance.

How to Optimise Largest Contentful Paint (LCP)

Many factors can affect a page Largest Contentful Paint and generally anything that improves overall loading times will decrease the LCP. Some areas to examine include:

Image Optimisation – Large files, such as images can greatly increase the overall size of a page and the time taken to download all assets. Ensure each image is properly sized

How to Optimise First Input Delay (FID)

First input delay is most commonly affected by long execution times of large scripts, so try and minimise this wherever possible.

How to Optimise Cumulative Layout Shift (CLS)

Most improvements to CLS are made by ensuring a page is rendered in the appropriate order and with defined spacing for each asset.


Hopefully this will help you better understand Core Web Vitals, why they are important in 2021 for SEO, and how you can improve your Core Web Vitals.

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