To understand what is wrong with your website and improve the Core Web Vitals, you must test and measure these metrics.

A bunch of free SEO tools are available to measure Core Web Vitals. 

In the article, we will cover:

  • The Google Tools to test the Core Web Vitals
  • Free SEO tools by third-party companies to measure the Core Web Vitals

Google’s Tools measuring the Core Web Vitals

The Core Web Vitals are a ranking factor for Google Search. It makes sense that Google offer a set of tools to help SEO and Webmaster understand if their website passed or not the threshold of the LCP, FID and CLS.

Google's Tools measuring the Core Web Vitals

Chrome User Experience Report (CrUX)

The Chrome User Experience Report (CrUX) is a set of public data on the real user experience on millions of websites.

This data is retrieved by Google when a user agrees to send statistics via Chrome or other services.

This database comes with an API that allows any developer to retrieve performance data for your or your competitors’ websites.

It is the only reliable way to know how your users feel about your site’s performance as it provides field data (and not lab data).

Keep in mind that the data provided by CrUX is a rolling average over the previous 28 days. It means it is not real-time data.

Chrome User Experience Report (CrUX)

You need coding skills to exploit this database and integrate it into your website diagnostic workflow.

To start with the CrUX API, it’s here.


Lighthouse is an automated audit tool and produces a diagnostic report to improve the user experience by showing you the problems found on your page.

Lighthouse is directly integrated into the Chrome development tools under the “Audits” panel.

Since Lighthouse 6.0, settings related to Core Web Vitals such as LCP and CSL are available in the report from the performance section.

It is possible to install Lighthouse via a Chrome extension and also to integrate Lighthouse into your website development and testing flow via your CI/CD pipeline with the Lighthouse CI.


Remember that Lighthouse is a Lab tool, and contrary to the CrUX data, it doesn’t show field data.

One comment on Field data vs Lab data

You must understand that the various tools presented on this page use real data and/or simulated data (Field Data vs Lab Data).

The real data is based on statistics collected by Google. Each time someone visits a website, they send data to Google about the performance (only if they opted in).

The data are real and are more accurate than simulated data. The inconvenience is that the field data are not delivered in real-time. 

Keep these two kinds of data sources in mind when testing your website against the Core Web Vitals:

  • Lab data is not a substitute for field data, but could help you speed up your testing process. 
  • Field data are used by Google for its ranking algorithm.

Page Speed Insights

Page Speed Insights (PSI) is accessible from this link and will give you information about the loading speed of a web page to optimize its performance.

PSI reports field data and lab data:

  • Field data coming from Crux
  • Lab data are coming from Lighthouse

Don’t get confused if the field data and lab data are not showing the exact same results.

Page Speed Insights

Web Vitals

Web Vitals is a Chrome extension that allows you to see at a glance how your page is measured against metric LCP, FID, CLS. It displays lab data and field data if available.

Web Vitals

The Chrome DevTools Performance Panel

Directly from your Chrome browser, you can access the DevTools and the performance panel showing lab data about the Core Web Vitals.

The Chrome DevTools Performance panel includes a new Experience section that can help you detect unexpected layout changes.

This section is helpful to find and correct visual instability problems on your page and fix the cumulative layout shift (CLS).

The Chrome DevTools Performance Panel

Core Web Vitals in Search Console

Core Web Vitals report is available from Google Search Console.

This report tells you which groups of pages on your site need special attention, based on field data from the CrUX.

Please note that the Search Console group similar pages together. Google groups them based on similarities such as template or type.

Core Web Vitals in Search Console allows you to measure the performance of your page over time. The data is the same as the Page Speed Insight report.

Free SEO tools to test the Core Web Vitals


Thruuu is an awesome SERP analyzer and offers many features, including a SERP Performance analysis. 

You can compare the pages speed and Core Web Vitals of every page on the Google SERP. It is really helpful to make a competitive analysis and understand if you need to optimize your site to win some ranking positions.

thruuu - Core Web Vitals

Reddico SERP Speed

The SERP Speed analysis from Reddico focuses solely on page performance. It provides a report for the top 10 pages on the SERP and as well some insights to improve your website.

Reddico SERP Speed

Layout Shift GIF Generator

Layout Shift GIF Generator, as its name indicates, generates a GIF showing the Cumulative Layout Shift (CLS) on a web page.

It helps you quickly figure out the shifting part of your web page.

Layout Shift GIF Generator

PageSpeed Compare

With PageSpeed Compare, you can enter several URLs and show a report comparing Core Web Vital metrics.

The UI is pretty neat, and in one sight, you can get a great comparison of pages performances and other data coming from the Google Page Speed Insights API.

PageSpeed Compare


Waterfaller is a free tool by Tim Bednar that helps fix and understand Core Web Vitals issues on a website.

It generates an audit or guidebook perfectly tailored for a development team. The guidebook represents user stories for developers to indicate the task to perform.

For instance, a user story could be “As a developer, I want the root document server response time to be less than 500ms in order to improve all Core Web Vitals.”

On top of this, the task can be sent to a Trello board. You could manage the improvement of your website from there with your team.


Measure Core Web Vitals with Google Sheets

If you are a heavy user of Google Sheet, this one is for you. Here is a Google Sheet that automates measuring the Core Web Vitals for multiple websites. You can enter several URLs and visualize the metric’s changes over time.

Measure Core Web Vitals with Google Sheets

Performance Report with GTmetrix

GTmetrix offers a free plan to test and monitor your website. You will get a summary of key performance indicators and the Core Web Vitals.

If you start paying, you can get a monitoring over time of your key metrics and the capability to test from various locations.

Performance Report with GTmetrix

RUMvision Free Core Web Vitals checker

RUMvision offers a free Core Web Vitals checker.

The UI is very user-friendly, and with one click, you get a report about your website’s performance. The Pagesepeed report is based on anonymised Google Chrome and gives you a Pagespeed UX score.

It also indicates what your domain ranking is, based on the domains that are tested. When you’re being tracked by a competitor that uses the paid plan, they will let you know this in the results.

You will get information about the main Core Web Vital metrics in the detailed results. Besides the Core Web Vitals, you will see how your TTFB, FCP and INP perform.

Go Further with the Core Web Vitals

Page Experience Optimization Workflow with Google Search Console: The Google Search Console (GSC) gives all the information you need about the Core Web Vitals for your website. You must understand to take advantage of this information.

Tips to improve Core Web Vitals: Start optimizing your website by following best practices. 

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