Core Web Vitals Field data vs Lab data: What they are?

Last updated on September 14, 2022 | By

Field data is the one used for Google for their algorithm ranking. Lab data is data using a simulated device meant to help you identify improvement points.

Cloudflare Web Analytics offers a tool that updates your Core Web Vitals data constantly with new data showing shortly after seeing a request from an user.

What is Core Web Vitals field data and lab data?

Field data from Core Web Vitals is a historical report about how a particular URL has performed and represents anonymized performance data from users in the real world on a variety of devices and network conditions.

The Core Web Vitals field data is aggregated from users who have opted-in to syncing their browsing history, have not set up a Sync passphrase, and have usage statistic reporting enabled(taken from a post on Search Console Forum). Field data is the one used for Google ranking.

Core Web Vitals lab data is data based on a simulated load of a page on a single device and a fixed set of network conditions. As a result, the values between lab data and field data may differ.

How to get or check Core Web Vitals field data

To get Core Web Vitals field data, you can use Cloudflare Web Analytics, which is free, privacy-first analytics that does not require you to change your DNS or use Cloudflare’s proxy. It does not collect or use your visitor’s data according to Cloudflare.

The data in the Search Console (Chrome UX Report) is a 28-day rolling average of aggregated metrics, so you need to wait until you can see changes reflected in the data.

With Cloudflare Web Analytics, you get data instantly no matter what your website visitors count, and you can adjust its Core Web Vitals according to the errors reported. You can filter by country, and analyze if a change is pertinent.

How to set up Cloudflare Web Analytics

To get started with Cloudflare Web Analytics follow the steps:

  1. Visit Get started with Web Analytics.
  2. Enter your Email address and password.
  3. Click Create Account.
  4. Enter your website’s hostname and click Next.
  5. Copy the JS Snippet and add it to any of your website’s HTML pages before the ending body tag.
  6. Click Next.
  7. Wait for the redirect to the Web Analytics page or click View Analytics. It may take a few minutes for Web Analytics data to appear.

Once enabled, find and copy the JS Snippet on the left menu of the Web Analytics page anytime.

Why should you use Cloudflare Web Analytics to measure Core Web Vitals?

RUM (Real User Measurement) data is more accurate than any synthetic tool, such as Pagespeed(lab data) or Webpagetest. Using Cloudflare Web Analytics will get you a real sense of your user experience and instant feedback on your Core Web Vitals.

Instant Core Web Vitals data from Cloudflare

You can also use RUM tools such as Google’s Chrome User Experience Report (CrUX), but it will take at least 28 days for the data to be refreshed.

Cloudflare Web Analytics features

Cloudflare Web Analytics lets you view your website’s page views, visits, page load time, and Core Web Vitals by switching between views on the graph. You can also filter data by various dimensions, all of this is offered for free on a top-notch UI/UX.

Cloudflare Web Analytics does not require you to change your DNS or use Cloudflare’s proxy.

Core Web Vitals is only supported in Chromium browsers, but Cloudflare says it has plans to support Safari and Firefox as soon as possible.

Images from

How to check historical Core Web Vitals field data offers a visualization of your Core Web Vitals real-world data(CRUx) through a UI, with access to data such as:

  • Core Web Vitals field data results by country.
  • Core Web Vitals field data results in 28-day or past-year aggregate.
  • Core Web Vitals field data results filtered by origins percentiles: P99, P95, P90, P75, P50, P25.
  • Field data results for experimental metric INTP(Interaction to next Paint), and Web Vitals FCP and TTFB.
treo report

How to measure Core Web Vitals and Lighthouse field data

Ahrefs offers Core Web Vitals field data for free in their Ahrefs Webmaster Tools product. It is necessary to verify ownership of your website to use it.

The performance audit shows both CRux data(used by Google for ranking) and Lighthouse data.

core web vitals ahrefs site audit

The tool is useful for identifying performance degradation in the website.

image 1

Leave a Comment