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Core Web Vitals


PageSpeed Insights v/s Google Lighthouse

Compare Google Lighthouse & PageSpeed Insights

James Gibbons
PageSpeed Insights v/s Google Lighthouse Hero Image

Understanding web performance metrics is essential to optimizing SEO for your website. Website performance is more crucial than ever in today's digital era as it affects your search engine rankings.

Offering a good search experience can benefit your company. Ensuring your website has the best page speed and loading time is essential to provide users with the best page experience.

Using Google's PageSpeed Insights and Lighthouse tools is one of the most effective and reliable ways to do this.

This article explains the differences between PageSpeed Insights and Lighthouse and how prioritizing your website's loading time will improve performance metrics.

We also look at how these two tools can help you identify and diagnose any issues with your website.

This article will help you be well-informed and better equipped to answer the question, "Which tool is better for measuring website performance: PageSpeed Insights or Google Lighthouse?"

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What is Google’s Page Speed Insights (PSI)?

Page Speed Insights is a free Google service that allows you to measure the technical performance of your website for desktop and mobile users.

Page Speed Insights (PSI) examines laboratory and real-world data using Lighthouse & Chrome User Experience Report or CrUX to make recommendations for a better user experience. Page Speed Insights assigns a number from 0 to 100 depending on how technically optimized your site is, with distinct values on desktop and mobile.

Google Page Speed Insights Report
Page Speed Insights Report by Google Page Speed Insights Test

PSI is an essential tool for SEO because it helps website owners understand the loading speed of their web pages, which can directly impact website rankings. The tool gives users an insight into how well their webpage is loading and what changes will improve its speed.

You can access the Page Speed Insights tool from here. Enter the URL to test, and press Analyze button to get the PSI report.

Understand Your Page Speed Insights Report

The Page Speed Insights report includes lab data, field data, opportunities, diagnoses, and passed audits. The report's color coding makes it easy to identify portions of the website functioning well, regions requiring development, and places underperforming.

1. A performance score below 50 is denoted by red, indicating that your site takes a long time to load on the device and that you will need further work.

2. A yellow range score (50-89) indicates that your page's loading times are fast, but you may need to make changes to increase performance.

3. Green denotes a fast-loading site with a performance score above 90.

Your PSI report assesses your web page for the following Core web vitals metrics:

1. Largest Contentful Paint: Measures how quickly the largest element of the page renders.

2. First Contentful Paint: Measures how quickly the page's main content is rendering.

3. First Input Delay: Measures how fast the page becomes interactive and usable.

4. Interaction to Next Piant (INP): Measures the time taken to switch from one page to another.

5. Cumulative Layout Shift: Measures the number of unexpected layout shifts in the page.

6. Time to First Byte (TTFB): Measures how long the web server responds with the first data byte.

Besides these, Page Speed Insights also ranks you for page performance, accessibility, best practices, and SEO scores.

What is Google’s Lighthouse?

Lighthouse is a Google open-source auditing tool that can be launched via the command line or as a Chrome plugin. Google Lighthouse helps you evaluate your website's performance, accessibility, and progressive web app (PWA) capabilities.

Google Lighthouse Report
Google Lighthouse Report

Lighthouse was launched in 2016 and has become one of the most popular web page auditing tools. A Lighthouse audit may detect possible problems with your website and provide specific measures to enhance its performance.

By inspecting your website using Lighthouse, your developers can guarantee a high-quality user experience and may discover any difficult spots before deploying new features.

To learn more about the Lighthouse report and how to utilize it for website speed, read our guide on the Lighthouse speed index.

Understanding Lighthouse Stack Packs

Lighthouse's most recent feature is Stack Packs. Stack Packs is a feature that will expand Lighthouse to include stack-specific suggestions to help solve specific audits.

These suggestions are more relevant than Lighthouse's standard general guidelines, which are incompatible with every tool and platform. GitHub community experts define and curate Stack Pack suggestions, so check out the official Github source for additional information.

The Lighthouse stack pack feature is currently available for WordPress but will soon be available for other CMS.

Page Speed Insights and Lighthouse: Similarities

Lighthouse and Page Speed Insights are tools developed by Google that allow website owners to analyze and optimize their web pages for better performance. Here is a list of similarities between these tools.

1. Free tools. Both PSI & Lighthouse are free to access and use.

2. Both tools provide a score from 0-100 that measures the overall performance of a page.

3. Expect an in-depth technical analysis of a website's speed, accessibility, and performance metrics from both tools. Get website improvements and optimization recommendations, such as minifying code, compressing images, pre-loading content, and using browser caching.

4. Both tools provide visual reports on each page that are easy to understand.

5. Lighthouse & PSI run directly in the browser or as part of an automated testing suite.

So when both these tools are so similar, why is it encouraged to use them? Do they give different insights and value? Let us understand in the next section.

Why are Page Speed Insights and Lighthouse Scores Different?

Lighthouse and Page Speed Insights are Google’s web performance testing tools, but their reports differ based on certain factors. Let us understand these factors and how they make the reports different.

1. Test Location

Test location refers to the geographic region from which the server ran the performance tests. It helps to provide an accurate assessment of real-world performance, considering the specific network conditions of the test region.

Page Speed Insights uses Google's servers worldwide. It is an automated tool that runs from Google's servers and tests how quickly page loads from various locations worldwide.

On the other hand, Lighthouse tests using the Chrome browser in your local environment. The manual tool runs from your local Chrome browser and reports on a page's performance, accessibility, and best practices.

Thus, Page Speed Insights is better for getting an overall view of a page's load performance. At the same time, Lighthouse is better for getting more detailed and actionable advice on improving a page's performance.

2. Network Throttling

It is an artificial method of slowing down network speeds, typically used to simulate different network connections on a web page. The network throttling technique tests a website's or web application's performance under various network conditions.

Network throttling measures modifications made to the website and determines if those modifications can improve the site's performance under those network conditions. Tests conducted with throttled connections can lead to a lower score provided by Lighthouse and Page Speed Insights.

Page Speed Insights runs the website without throttling on a fast connection and then simulates how the page would have loaded on a slower connection.

Lighthouse in Chrome DevTools allows you to select between simulated and browser-level "applied" throttling. In this case, the browser adds a delay to each network response.

3. CPU Performance

CPU performance measures how well your website's JavaScript code runs on the user's device or computer. CPU performance is essential for page speed, affecting the time the website loads and renders its interactive elements.

Google considers CPU performance when measuring website page speed, as slower CPU performance can lead to slower page loading and a poor user experience. By measuring CPU performance, Google can provide website owners with optimization tips to help improve their website's performance.

PageSpeed Insights measures the CPU performance of a page by evaluating the time it takes to fully load the page, including resources like images, JavaScript, and HTML. Performance time is then compared against the time it takes on average to complete the same process across all similar websites, allowing PageSpeed Insights to assign a score to the page based on its CPU performance. PageSpeed Insights also provides suggestions and optimization tips to help website owners improve their page's CPU performance.

Lighthouse audit reports include data on the page's CPU performance, including total CPU time, DOMContentLoaded time, and first contentful paint time. With this data, website owners can better understand what aspects of their site impact page performance and make the necessary adjustments to improve their website speed.

4. Chrome Version

Different versions of Chrome may yield different scores on Lighthouse and Page Speed Insights tests. Newer versions, for example, may include performance changes that make them speedier.

Page Speed Insights uses the latest version of Chrome, which may be different from the version used by the end user and can thus lead to inaccurate results. Lighthouse tests are conducted with the same Chrome version as the end user.

Browsers' methods for measuring performance indicators are evolving with time. Chrome changelogs can demonstrate how the definitions of First Contentful Paint, Largest Contentful Paint, First Input Delay, and Cumulative Layout Shift have developed with time.

5. Lighthouse Version

The version of the Lighthouse used to conduct the test can also impact the score. Google keeps updating the Lighthouse and changes the way tests are conducted over time, and the amount to which different indicators contribute to the overall performance score also varies.

Page Speed Insights does not consider the Lighthouse version. It uses a standard version for testing. Lighthouse, on the other hand, accounts for which version of Lighthouse the user is using.

6. Different Settings

Lighthouse and Page Speed Insights have different timeout settings that determine when a test will end. Lighthouse and Page Speed Insights may give different results depending on how quickly a page renders or finishes loading, so it's essential to understand the timeout settings for both tools.

Page Speed Insights does not consider additional settings that may be enabled or disabled in the Chrome browser. On the other hand, Lighthouse considers any additional settings that may be enabled or disabled in the Chrome browser.

7. Chrome Extensions

Certain chrome extensions can also affect the score. For example, Chrome extensions might affect your performance ratings if you run Lighthouse in Chrome DevTools.

Page Speed Insights ignores any extensions users may install in the Chrome browser. However, Google Lighthouse considers any extensions installed in the Chrome browser.

To conduct tests with extensions disabled, use Incognito mode or a new Chrome profile.

Overall, PSI evaluates the page as if an HTTP request was visiting it, and the scores reflect how well the page is optimized for performance. Lighthouse provides more detailed and in-depth information about the performance of a particular web page with optimization suggestions.

Comparing Page Speed Insights & Google Lighthouse

PageSpeed insights and Google Lighthouse tools are two widely used web performance analysis tools to measure website performance and user experience. Comparing the two tools is beneficial for web developers, as it helps them identify the weaknesses and strengths of their sites to the two tools.

Both these tools because they are robust, free-to-use, and reliable tools to evaluate website performance, each with pros and cons. Comparing these two tools can help people identify the best tool for the specific tasks they wish to accomplish.

Let us compare Page Speed Insights and Lighthouse against some of the top features.

Page Speed Insights v/s Lighthouse: Data Sourcing

Page Speed Insights and Lighthouse use two types of data, i.e., lab and field data.

Lab data consists of performance metrics and timing information from a server or web browser for a specific page URL. This data can provide valuable insights into the performance of a webpage and its components, helping website owners and developers identify potential areas for improvement. Examples of lab data when measuring page speed include time to first byte, server response time, page size, time to render, page load time, page speed score, number of requests, and more.

Lab data is acquired by:

1. Using various web page testing platforms such as Google’s PageSpeed Insights, WebPageTest, and Pingdom

2. Using APIs from testing services to periodically measure page speed from multiple locations

3. Tracking performance metrics from a real user’s browser session

Field data is real-world user experience data collected from devices and networks worldwide. Collected data may include page loading time and time to the first byte, which allows you to see how the page performs in the real world.

PSI retrieves and analyzes the website using Lighthouse, which simulates how a page loads on a device. It includes performance metrics such as First Contentful Paint, Time to Interactive, & Speed Index and summarises these data with a performance score ranging from 0 to 100. Lab data helps show how a page performs on a simulated device in a controlled environment and is helpful for debugging issues.

The Google Page Speed Insights field data displays the last 28-day report. It comprises aggregated data from the CrUX report with data from real-world Chrome users.

Page Speed Insights shows you insights into the performance of your website based on lab & real-world data. In contrast, Lighthouse measures all elements of a website, such as SEO, performance, best practices, progressive web apps, and accessibility based on lab data.

Page Speed Insights v/s Lighthouse: Metrics

Google Lighthouse and PageSpeed Insights tools measure performance against various metrics such as loading time, resource size, code quality, and image optimization.

When comparing Lighthouse and PageSpeed Insights tools, one of the first considerations is the type of metrics they measure. Lighthouse measures 13 metrics, including performance, accessibility, best practices, and SEO, while PageSpeed Insight measures six metrics, like loading time, resource size, code quality, and image optimization.

Lighthouse performs a comprehensive audit of your web page, providing insights on performance, accessibility, best practices, and more. Specifically, Lighthouse provides the following metrics:

1. First Contentful Paint: 10% weightage

2. Speed Index: 10% weightage

3. Total Blocking Time: 30% weightage

4. Largest Contentful Paint: 25% weightage

5. Cumulative Layout Shift: 25% weightage

Metrics Measured by Lighthouse Report
Metrics measured by Lighthouse report

While calculating the performance score, Lighthouse gives different weightage to each metric. The weightage signifies the importance of each metric in calculating the overall performance score.

It is thus essential to keep an eye on each of these five metrics to maintain a successful website. By paying attention to the weightage of each metric, web administrators can focus on improving the aspects of a website that are more important to overall performance. Improving each metric may improve overall website performance and page speed.

Lighthouse powers page Speed Insight reports. Due to this reason, apart from the metrics measured by the Lighthouse, Page Speed Insights also measures your website's Core Web Vitals based on field data. The core web vitals metrics include:

1. First Input Display

2. Interaction to Next Paint

3. Time to First Byte

To summarize, PSI reports include all the information the Lighthouse provides, but vice-versa needs to be validated by running the Lighthouse audit.

Reports in PSI v/s Lighthouse

Page Speed Insights can measure the performance of one page at a time. On the other hand, the Lighthouse can measure the performance of multiple pages simultaneously using Lighthouse-CI Command multiple times.

You can also run another CLI package, Lighthouse parade, which will check the performance of all the discoverable pages through the URL you provide. You can use the following code:

npx Lighthouse-parade

Alternatively; you can also use Lighthouse batch, another CLI package that will test multiple pages simultaneously.

Lighthouse-batch -s,,

Learn more ways to check your Lighthouse report for multiple pages simultaneously.

Page Speed Insights v/s Lighthouse: Use Case

Page Speed Insights tool is ideal for web admins, marketers, and other web professionals who need to improve their website's performance. Everyone can use it to identify potential issues with a website, such as slow loading times, poor caching, and other performance-related issues.

On the other hand, Lighthouse is used primarily by developers to evaluate the performance and accessibility of a web page. It uses a CLI or browser extension to provide more in-depth feedback on code-level issues like JavaScript errors, HTML structure problems, and other technical matters that developers better understand. It's a great tool to help developers identify and fix potential issues with web pages.

We capture all these factors in a summary table below:

Factors Page Speed Insights Google Lighthouse
Data Sourcing Methods Lab + Field Data Lab Data
Metrics Measured Includes metrics based on real-world and controlled environment Includes metrics based on controlled environment
How to Access Report? Using Page Speed Insights Tool 1. Chrome Dev Tools
2. CLI (Lighthouse Node Module)
3. Lighthouse API (Node Package)
4. Chrome Extension
Control Over Data Less More
Number of Pages Accessed One page at a time Multiple pages at a time
Use Case Marketers, Webmasters, and other web professionals Developers

Page Speed Insights or Lighthouse: Which one to Choose?

Page Speed Insights and Lighthouse are valuable tools for optimizing the performance and accessibility of your website. The choice of tool depends on the needs of your website and business goals.

Let us look at the scenarios in which each tool would be beneficial:

When to Use Page Speed Insights?

1. If you are only interested in checking your website's page loading speed, Page Speed Insights is an excellent choice. It will show you your website's page loading speed and advise you on how to improve it.

2. Use PSI when you want a comprehensive report of the loading times experienced by your website's visitors across the globe.

3. Use PSI reports if you are not a big fan of using Chrome developer tools for analyzing your website's performance. It provides a more accessible interface and more detailed results than Chrome developer tools, which can be challenging to navigate for non-programmers or marketers.

When to Use Google Lighthouse?

1. Lighthouse is better for an in-depth report about your website's performance, accessibility, and SEO. You can use Lighthouse to evaluate and know precisely how your website performs under specific user environments.

2. Evaluate various aspects of a website's performance programmatically to automate the process using Lighthouse. The Lighthouse API enables you to incorporate the results of the audits into your systems. It means you can automatically monitor your website's performance and gain insights into the areas needing improvement without manual audits.

3. Use Lighthouse to track specific metrics such as time to first byte, DOM size, and time to interactivity.

4. Google Lighthouse also allows you to test your website performance for mobile browsing.

5. You can also use the Lighthouse to share the performance report with your team members. You can quickly download and share the report in multiple formats.

Final Thoughts on PageSpeed Insights & Lighthouse

Monitoring the performance of your website may help you enhance the user experience and increase website traffic. PageSpeed Insights and Lighthouse are two standard tools for tracking page speed and website performance.

Page Speed Insights and Google Lighthouse have advantages and disadvantages, but they work best together to provide a comprehensive view of your performance.

While Lighthouse provides a more comprehensive view of data, Page Speed Insights delivers a more accurate picture of how web pages perform for actual visitors. You may use both to acquire suggestions for enhancing your website's front and back ends. The more data you have, your site modifications will be successful.

Testing the performance of all your web pages becomes challenging when using any of these tools. It would be best if you had an enterprise tool that can analyze all the pages of your website simultaneously, and you don’t need to test each page manually.

SEO platform such as Quattr becomes handy if you want to check the performance of all your web pages in one go. Various Quattr features help identify page performance issues on your website and suggest strategies to improve page load time.

Page speed optimization prioritized recommendations using Quattr
Improve page performance & test scores before publishing in Quattr's Sandbox Environment

Quattr will present you with prioritized enhancements based on anticipated traffic gains. You will also receive insights and an evaluation of how these efforts will affect your business objectives and increase the ROI of your business and website.

Improved page speed and user experience are essential to maintain any website's visibility, engagement, and reputation in today's increasingly competitive digital landscape. Hence, web admins should use these valuable tools to analyze and optimize their websites' performance & user experience.

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Google PageSpeed Insights v/s Lighthouse FAQs

Is Lighthouse the same as Page Speed Insights?

No, Lighthouse and Page Speed Insights are not the same. Page Speed Insights is a tool that provides performance scores and suggestions for improving performance on a website based on lab and field data. Lighthouse is an open-source, automated tool that creates audit reports on website performance, accessibility, best practices, and more based on lab data.

Why are Lighthouse & PSI scores different?

Lighthouse and Page Speed Insights scores differ because each tool has different methods for measuring performance. Lighthouse scores are based on performance metrics, while PSI scores are based on a simulated load test.

Which tool is better for SEO - Google Lighthouse or Page Speed Insights?

Both tools are helpful for SEO. Google Lighthouse is a more comprehensive tool. It evaluates a website's performance from a technical and SEO perspective. While Page Speed Insights uses, Lighthouse reports providing insights into a website's loading speed and tests on worldwide servers.

Why should you use both Lighthouse & Page Speed Insights?

Using both Google Lighthouse & Page Speed Insights (PSI) together gives you a complete understanding of your website's performance. Lighthouse can provide deeper insight into technical performance, while PSI can help you identify slow-loading areas and take steps to optimize them.

About The Author

James Gibbons

James Gibbons is the Senior Customer Success Manager at Quattr. He has 10 years of experience in SEO and has worked with multiple agencies, brands, and B2B companies. He has helped clients scale organic and paid search presence to find hidden growth opportunities. James writes about all aspects of SEO: on-page, off-page, and technical SEO.

About Quattr

Quattr is an innovative and fast-growing venture-backed company based in Palo Alto, California USA. We are a Delaware corporation that has raised over $7M in venture capital. Quattr's AI-first platform evaluates like search engines to find opportunities across content, experience, and discoverability. A team of growth concierge analyze your data and recommends the top improvements to make for faster organic traffic growth. Growth-driven brands trust Quattr and are seeing sustained traffic growth.

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