Core Web Vitals: three new ranking metrics from Google

September 1, 2020
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Google organizes site races. Prizes will be taken by the fastest. On May 5, the company announced new parameters of the sites that will be taken into account during the ranking. Their name is Core Web Vitals. The launch is planned for 2021 and that’s when the fastest will get to the top. Of course, the innovations do not cancel the current factors that affect the promotion of the site on the top, there are several hundred in Google. In the meantime, there is time to understand in detail and prepare your web pages for the new requirements.

What is Core Web Vitals?

The main goal is to make the online experience comfortable for the user. In addition to the more well-known ranking factors that take into account User experience (UX): mobility, secure browsing, HTTPS, and the absence of annoying windows, Google’s algorithm will take into account parameters that will measure the speed of websites. But what does that mean? What, where, and how much should be accelerated? Google employees have formulated 3 indicators that will be evaluated and combined them under the term Core Web Vitals:

1. Largest contentful paint (LCP)

Largest contentful paint (LCP) – drawing the largest content. Measures the time it takes for the largest visible page item to load. This is most often a video, picture, or three-dimensional text block.

Why this indicator?

Metrics that existed before LCP do not take into account data that the user sees on the screen (DOMContentLoaded and Load) or are too complex and

often erroneous (First Meaningful Paint (FMP), Speed ​​Index (SI)). Therefore, it is not possible to determine whether a site visitor is satisfied with the download speed. Experts have concluded that the best measure will be the time during which the largest element of the page emerges.

In numbers

For LCP and the following ranking factors, the developers proposed 3 indicators:

  • good (green area)
  • need improvement (yellow zone)
  • not enough (red zone)

It is good if the largest element of the page is displayed in 2.5 seconds. Get into the red zone after 4 seconds.

What to look for if the site is in the red zone?

  • large items. If possible, it is better to remove them.
  • carefully with scripts. Each third-party script slows down page loading
  • upgrade your web hosting
  • set up a delayed download. Then the items will be loaded during scrolling.

2. First input delay (FID)

First input delay (FID) – delay the first input. A metric that shows the delay of the first input when the page loads. Simply put, it’s how fast the site is ready to work with the user. Enter text, upload a picture, click on a link, etc.

Why is FID an important ranking factor?

How quickly your site becomes available for interactive interaction will determine the customer’s first impression. Plus, many sites have trouble being willing to interact with the user during download, which is very annoying to visitors.

In numbers

Good time up to 100 milliseconds, bad – more than 300 milliseconds.

What to pay attention to if the site reacts for a long time?

  • Third-party scripts. Buttons on social networks, analytics service – all this slows down
  • “Heavy” code. While the site analyzes HTML, CSS, and JavaScript, it will not be able to respond to client requests.

3. Cumulative layout shift (CLS)

Cumulative layout shift (CLS) – cumulative layout shift. Layout stability indicator. With CLS, you can quantify how often a user encounters unexpected item shifts while loading a web page.

Why is it important?

Will protect against unwanted conversions (accidental click on ads, enhancements, etc.) and disorientation on the site. Uncontrolled movement of text, buttons, links is very annoying to users.


Ideal if the CLS does not exceed 0.1. If this figure is greater than 0.25. means serious problems on the site.

What to do then?

  • Fix the size of images and videos
  • Do not paste content on top of other content
  • Prefer conversion animation over property animation.

Why do Core Web Vitals make an important ranking factor?

The sooner the site loads, the more it is ready to interact, the less it will irritate the user with unpredictable “actions”, the more pleasant it is to use. This will affect search positions and traffic. More traffic – more conversions – more business revenue.

Core Web Vitals are well-defined metrics that help quantify the above metrics. But even though they are not officially considered ranking factors, they have long influenced the optimization of the site.

Many users leave the “sluggish” web resource, the Google algorithm sees that something is wrong with the resource and offers better, more convenient options. Therefore, speed and without official recognition are very important for User experience (UX) and SEO, which affects the conversion.

For example, (French online store of ski equipment and clothing) reduced the download time by 1.9 seconds and reduced the speed index by 10 times and its conversion increased by 94%.

How to measure Core Web Vitals?

Methods of metric analysis are divided into field and laboratory.

Field methods – for fast and real monitoring of web experience.

  • PageSpeed ​​Insights – shows how the page interacts with the user and offers optimization options.
  • Web Vitals browser extension – you can go to the official Chrome app store and extensions store. Shows the open page report directly in the browser.
  • Google Search Console (Core Web Vitals report) – a tool that will allow you to measure impressions in more detail. Shows problem pages depict digital values ​​of metrics, gives options for improvement.

Laboratory (for web developers) – allow you to diagnose problems during the development of the site.

  • Chrome DevTools – built-in tools for site developers. Allows you to quickly fix problems
  • Lighthouse – a tool that automatically audits the site. Enter the URL and it provides a report on the page.


It is important for search engines that the user comes to the site and solves their problem on it. This is the main task of Google’s algorithms. The online resource must provide a quality user experience. Core Web Vitals are not the only indicators that determine the quality of the sites. But the behavioral factors that directly affect rankings largely depend on the download speed. The main customer, so everything is done for his convenience.