Google Lighthouse Vs. Google PageSpeed Insights—A Complete Guide

Posted September 10, 2021 by in Career

Lighthouse & PageSpeed Insights is quite similar technology yet they deliver different results. Both are used to measure the performances of web pages but through different approaches.  This predicament always leaves us confused about which analysis tool to use to check our site’s performance. However, these tools help you practice some web designs that can boost your website conversions. This guide will explain the key differences between both tools and when to use them.  

Let us shed some light on Lighthouse and PageSpeed Insights performance auditor tools:

What is Google Lighthouse And Google PageSpeed Insights?

PageSpeed Insights is a family of tools designed to analyze a site’s performance and make some general suggestions to optimize page speed. It focuses on the content of a webpage, its load time, its page time, and much more.

PageSpeed Insights uses both lab data and field data to drive cohesive results.

On the other hand, the Google Lighthouse is an open-source automated tool to analyze a site’s performance. On top of analyzing performance metrics, such as page speed & load time, etc., Lighthouse also enables you to analyze SEO, accessibility, progressive web app, HTTPS best practices, etc. 

Unlike PageSpeed Insights, it uses lab data only to debug performance issues. It does not support field data to analyze performance according to real-world experiences. Lighthouse is truly an SEO analyzing engine because it efficiently measures 5 prominent performance metrics.

Lighthouse Can Be Run In:

Web UI: It helps in the direct linking of reports without even downloading anything.

ChromeDev Tools: It easily audits pages that require testament in a user-friendly manner.
Node Module: It integrates lighthouse into your continuous integration systems

Command-Line: Uses Shell scripts to run Lighthouse.

PageSpeed Insights Provides:

Lab Data & Field Data

Field data is all about how good a URL’s overall performance is. It provides real-world experience to support your analysis from N number of networks, whereas the lab data is based on the simulated load of a page on a single device and fixed network. Also, the real-world data used by PageSpeed Insights comes from CrUX-Chrome User Experience Report.

Performance Score

Your website performance can score anywhere between 0-100. A score above 90 means your website is fast enough, below 50 is considered very slow, and the rest, between 50 to 90, is considered average. 


PSI will suggest how to improve your website’s performance through its performance metrics. Along with suggestions, it will also shed some light on the best web development practices.

Google Lighthouse Provides:

On testing the website’s performance via the Lighthouse analysis engine, without PSI, you will get a report on the following factors:

One: SEO

Two: Overall Performance

  • First Contentful Paint
  • Speed Index
  • First Meaningful Paint
  • First CPU Idle
  • Time To Interactive
  • Estimated Input Latency

Three: Best Practices
Four: Progressive Web App
Five: Accessibility

Earlier, PageSpeed Insights used other analysis engines to drive performance results. This process eventually failed because different analysis engines brought inconsistent results. PageSpeed Insights now uses Lighthouse initiated by Google to drive similar recommendations everywhere: web, Chrome DevTools, Command-Line. Now, Lighthouse and PageSpeed Insights are integrated into a single platform where you could make the most of your performance metrics. 

Out of all performance aspects, the ‘loading speed’ metric remains at the top whenever we gauge a website’s performance. A digital marketing Mississauga uses white-hat seo strategies that make website loading speed really fast. A fast loading speed delivers a good user experience along with the high authority that helps in improving search engine ranking.

The following performance metrics are thoroughly analyzed by PSI:

  • First Contentful Paint
  • Largest Contentful paint
  • Time to Interactive 
  • Speed Index
  • Cumulative Layout Shift
  • First Input Delay
  • Total Blocking time

How to run PageSpeed Insights and Lighthouse?

  • To run PageSpeed Insights, navigate to PageSpeed Insights and enter a web page URL. Click Analyze and you will be able to view reports online. 
  • To run Lighthouse in Chrome DevTools, you need to download Chrome first. 
  • After downloading, go to the URL you want to check. 
  • Now, open Chrome DevTools and go to the Audit tab.
  • Click on Audit. DevTools will show you a list of performance metrics. Leave them all enabled.
  • After running the audit, the lighthouse will share your performance reports on the page.

PageSpeed Insights basically measures performance metrics based on website and page load time, whereas Lighthouse measures SEO and accessibility aspects along with performance metrics.

  • Google PageSpeed Insights uses both- field data and lab data.
  • Google Lighthouse uses lab data only.

PageSpeed Insights can analyze the performance of a page on both desktop and mobile devices. It will also provide you suggestions on how to improve your page. Whereas lighthouse is known for providing personalized advice on how to improve your website.

Lighthouse and PageSpeed Insights altogether have driven consistent output and reduced confusion among developers. These types of tools truly care about your site’s optimization and search engine ranking. A website design Mississauga can also help you analyze your website and provide you complete SEO audit report by that can help you optimize your website.

*Photo by PhotoMIX Company