What Are Core Web Vitals?

Date First Published: 11th November 2022

Topic: Web Design & Development

Subtopic: SEO

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 6/10

CONTENTS

Measurements
Where To Find Core Web Vitals Data?

Learn more about what core web vitals are in this article.

Core web vitals are metrics used by Google to measure the overall user experience of a webpage. Core web vitals measures three main things, which are the page loading speed, layout shifts, and visual stability. Other web vitals not part of core web vitals are HTTPS, mobile friendliness, safe browsing, and intrusive interstitial ads. Google has announced that they are combining the signals that come from Core Web Vitals with their existing search signals for page experience.

Core web vitals was introduced by Google in May 2020 and they have confirmed that it is a ranking factor, but it is only a small ranking factor as a good loading and response time does not overwrite having high-quality content. This means that a page could still respond quickly to user interactions, load quickly, and have low-quality content.

Measurements

The three main things that core web vitals measure are:

Largest Contentful Paint (LCP)

LCP measures the period of time between the user loading the page and the largest image, video, or block of text being rendered in the viewport (current screen). Nothing outside of the viewport is considered.

The range of LCP scores are:

Less than 2.5 seconds - Green (Good)
2.5-4.0 seconds - Orange (Fair)
More than 4 seconds - Red (Poor)

Cumulative Layout Shift (CLS)

CLS measures the total of all individual layout shift scores for every shift that occurs when the page is loaded. The score can range from 0 to a positive number, where 0 means no shifting at all and the larger the number, the more layout shifts on the page.

Sometimes, links or buttons can unexpectedly shift or move around after the page has loaded and users can become irritated by that, especially if they shift whilst the user is reading. CLS determines how much elements shift on the page so that website owners can improve the usability and overall user experience of a page.

The range of CLS scores are:

Less than 0.1 - Green (Good)
0.1-0.25 - Orange (Fair)
More than 0.25 - Red (Poor)

First Input Delay (FID)

FID measures input latency, which is the period of time that it takes for an element to respond after a user’s input. It is the time from when a user interacts with a website, such as clicking on a link or a button, using a JavaScript function to the time that the web browser can respond to that interaction. Users want pages that respond quickly to their actions without leaving them waiting for a response from their browser for long periods of time. FID only records events like clicks and key presses.

Note:

Sometimes, this metric also depends on things outside of the website owner's control, such as the device capability of users and internet speed.

The range of FID scores are:

Less than 100 milliseconds - Green (Good)
100-300 milliseconds - Orange (Fair)
More than 300 milliseconds - Red (Poor)

Where To Find Core Web Vitals Data?

Core web vitals can be found in Google Search Console. The core web vitals report displays URL performance and URLs are categorised by status, metric type, and URL group. Only URLs indexed by Google can appear in the report.

Sometimes, the report may return blank and say ‘no data available’. This means that the property is new in Google Search Console or there is not enough data available in the Chrome User Experience (CrUX) report to provide useful information for the chosen device type.