Documentation

Web Vitals

Core Web Vitals is a suite of performance metrics that give you an overall picture of the user experience on your website. The metrics are based on Google's Lighthouse project, which reports on a number of different performance criteria. The Core Web Vitals score for each metric ranges from 0 to 100, with 100 being the best possible score. A higher score indicates better performance.

Largest Contentful Paint (LCP)

The first web vitals metric is Largest Contentful Paint (LCP). This web vital measures the time in seconds that it takes from the page to start loading to when the largest webpage element pops up on the screen.

The goal of measuring this web vital is to determine the estimated amount of time that it takes for the main elements of a web page to load. In other words, it determines how fast your web page pops up for visitors to use.

First Contentful Paint (FCP)

First Contentful Paint is the time at which the browser displays any text, or partial text, or even an image that indicates that the page is loading. In other words, it’s when the user can see something on their screen.

First Input Delay (FID)

First Input Delay (FID) is another web vitals metric that considers time. It measures the time in milliseconds between the first time a user interacts with your site to when the browser reacts to that interaction.

Cumulative Layout Shift (CLS)

Cumulative Layout Shift (CLS) measures the cumulative score of all of the unexpected layout shifts that occur while a visitor is looking at your web page. If any page elements move around while a visitor is looking at them, that may negatively impact the ranking of your site.

Time To First Byte (TTFB)

Time to first byte measures how long it takes for a browser to receive its first byte of data from a server after making a request for a resource on a page. It’s important because it indicates how fast information is sent over HTTP/2 connections between browsers and web servers. A faster TTFB can help users perceive faster page load times.

What is Real Experience Score?

Real Experience Score(RES) is a weighted measure of all core web vitals combined. It takes into account many factors, including page load speed, time to first byte, render time and more. RES is Google’s way of measuring how well a web page performs overall and gives you an indication of how fast your site loads for users. The higher your RES score the better it is for SEO because Google uses this metric when ranking pages in search results.

How scores are determined?

Scores for Core Web Vitals are calculated using weights we’ve chosen based on research and analysis of the user experience. We use these weights to calculate a score for each core web vital, which we then combine into a single Real Experience Score. The higher your Real Experience Score, the better it is for SEO because Google uses this metric when ranking pages in search results.

Due to different device types values for weight are slightly different. The following table shows the weights used for each core web vital. The weight is multiplied by the value to calculate a score, which is then combined with scores from all other core web vitals to determine your Real Experience Score.

How the scores Are Color-Coded?

Green: This is a healthy site! It has no critical errors, one or two informational errors and no usability issues.

Yellow: This site has many informational and usability issues, but no critical errors. We recommend addressing these issues as soon as possible to improve your score.

Red: This site has multiple critical errors that are affecting the user experience and functionality of the site.