Google Lighthouse An Overview

Google Lighthouse

Table Of Content


Google Lighthouse is an open-source tool that assesses the performance, accessibility, progressive web app, and other website aspects, providing improvement recommendations.

Getting the most conversions or selling the most products isn’t the primary goal of the most successful websites. The quality of those features is certainly important, but user experience comes first.

The performance of your website can be used to gauge the user experience (UX). When your website is slow, the user experience suffers. Users won’t even notice if your website loads – it is generally accepted that a site loses visitors after a couple of seconds.

To evaluate your site’s UX, an outside consultant isn’t necessary or even necessary to redesign it. With Google Lighthouse, your website is audited by Google to see how it compares to others. Because it’s Google, it makes sense to pay attention.

What is Google Lighthouse?

The Lighthouse tool, whether called Lighthouse or simply Lighthouse, is a free tool used to assess web page quality.

Lighthouse measures the quality of any public page anywhere on the web, evaluating them according to five criteria: speed, usability, SEO, and certification with PWA.

Site owners can use these categories to measure usability on web pages as part of core web vitals tracked by Google. Lighthouse provides suggestions for improving the overall user experience in each of these categories.

Lighthouse is easy to use and provides valuable insights for both new and experienced webmasters alike. While website optimization can be a dense topic for new webmasters, Lighthouse isn’t.

All you have to do is enter the URL, and Lighthouse will do the rest, including recommendations for further reading about each issue.

By providing a more realistic and comprehensive assessment of a page’s overall quality, Google Lighthouse distinguishes itself from other popular website assessments.

The page speed is not the only factor taken into account; accessibility, indexability, and well-business are also important. Furthermore, it is open-source, which means it can be integrated into other web-based tools.

Google Lighthouse Metrics

The Lighthouse system grades the first four categories from zero to one hundred based on their overall quality. Scores from 0 to 49 (triangle) indicate poor performance, 50 to 89 (square) is a fair performance, and 90 to 100 (circle) indicates excellent performance.

It is very difficult to achieve a 100/100 grade for Lighthouse and Page Speed Insights. Therefore, don’t strive to get perfect scores – you’ll be fine as long as you get green.

Lighthouse reports provide insight and suggestions for improving your pages based on each score. Without a Lighthouse report, these scores wouldn’t be useful to us. Let’s take a closer look at each one.


With Lighthouse’s performance assessment, you are able to perform an enhanced speed test for your website.

When evaluating website performance, there are two important considerations many don’t give much thought to.

A visitor’s internet connection or the device they’re using might be different from your own. Mobile devices make up nearly half of all internet traffic worldwide, and they connect over relatively slow connections, which affects loading time greatly.

Additionally, you can’t just sum up the time it takes for a page to load in one number. The speed at which a website appears to a viewer is affected by several factors, from how long it takes to load any content to how quickly it allows users to interact with it.

As a result of these improvements to Google Lighthouse, the latest version (1) simulates the load time of pages on mobile devices, and (2) calculates your Performance score based on 6 metrics:

  • An image of a piece of text that first appears on-screen fully rendered is known as the First Contentful Paint.
  • A page is fully interactive after a certain amount of time has passed. Thus, the majority of user actions and inputs are processed within 50 milliseconds.
  • During the Total Blocking Time, users can view content but not interact with it. It occurs between the First Contentful Paint and the Time to Interactive.
  • Your site’s speed index determines how fast the visual elements of your site load completely.
  • It is the duration it takes to fully render the element with the largest amount of text or image.
  • Layout shifts are counted cumulatively as the total number of unexpected changes on a page. It can cause interaction issues for the user if they click in the wrong place at the wrong time if an element unexpectedly shifts from one location on the page to another:

Below Metrics, Lighthouse provides Diagnostics and Opportunities, which suggest ways to improve performance for each page. There are several things you can do to make your content load faster, such as removing rendering-blocking or unused code, making your code more efficient, and optimizing your images.


Your page is then graded by Lighthouse based on accessibility for people with mental and physical disabilities.

Access to public information on your website should be accessible to all visitors.

In addition to accessibility audits, Lighthouse performs several other checks, such as evaluating the code structure and semantics of HTML tags, utilizing alternative text and applying ARIA landmarks, and testing the language of the pages.

In case your accessibility score is less than ideal, usability for everyone can be improved using our web accessibility checklist and our guide to accessibility on the web.

Best Practices

In addition, Lighthouse audits widely accepted web development best practices. This includes ensuring that HTTPS is used, safe links are used, and that JavaScript libraries and APIs are current – but it can also try to ensure that your images are displayed in an appropriate resolution and that the HTML doctype is specified.


A page’s SEO score reflects the degree to which it adheres to SEO best practices as the last graded category. A good use of the HTML tags and attributes ensures that these tests check whether your page is crawlable.

If any tests fail, see our Ultimate Guide to On-Page SEO for addressing issues associated with this category. Lighthouse’s SEO report is pretty basic, but it can help you boost your rankings almost immediately.

Progressive Web App

We check your site’s final performance to be sure it meets Google’s standards for a Progressive Web Application, one that can be accessed via any device and from any location. The Lighthouse software was originally designed for this assessment, and it remains a valuable feature.

There is no score assigned when you take the Progressive Web App test, but it indicates if you pass or fail. Performance, responsiveness, and other factors are assessed to make sure your web application meets the standards of your target audience.

Dwell time

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