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Core Web Vitals


Google Lighthouse Page Speed Index Guide

How to Utilize Lighthouse to Analyze & Improve Page Speed Index

James Gibbons
Google Lighthouse Optimization Hero Image

Page speed is a crucial factor in the success of any website. It affects everything from user experience to SEO rankings. Thankfully, there is a free tool that can help you analyze and improve your page speed index - Google's Lighthouse. 

With Google Lighthouse, you can quickly and easily assess the performance, accessibility, and SEO of your site. It also provides advice on how to optimize your page for maximum performance. 

This blog post will teach us how to utilize Lighthouse to analyze and improve your page speed index. Understand how to identify and address performance and loading issues and use the Lighthouse reports to optimize your pages and increase your page speed index.

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Google Lighthouse Introduction

Google Lighthouse page speed is a free tool that may help you enhance your website by providing the necessary information. By creating a Lighthouse report, you may examine any web page's experience and receive vital advice to improve its performance.

Google has increasingly emphasized on-page experience, adding a new Core Web Vital signal set. The signals describe how a person interacts with your page, and Lighthouse can show you how your website performs in this area.

Because the Lighthouse speed test is a Google tool, it might be a terrific method to see your website as Google sees it, knowing that any recommendations come directly from the search engine giant.

Google Lighthouse report
Lighthouse report

Google Lighthouse diagnoses your web page and provides you with five audit reports.

1. Performance: Measure a web page's load time and how it responds to user input.

2. Accessibility: Analyze how well the web page meets accessibility standards. Some of these include keyboard navigation, color contrast, and text size. 

3. Best Practices: Identifies potential coding issues, such as standard errors, deprecated API usage, and more. 

4. SEO: Reviews the web page's visibility and indexability in search engine organic search results. 

5. Progressive Web App: Assess whether the web page is suitable as a Progressive Web App (PWA). It includes checking service worker registration, TLS requirements, and safer HTTPS requirements.

Lighthouse is a terrific speed-testing tool because it provides actionable information while being simple to use. You may obtain thorough page experience information in only a few clicks, offering essential insights into optimizing performance.

Lighthouse Metrics
You can track various metrics in a Lighthouse report

It is available as a Chrome extension, in the Chrome DevTools, or as a command line tool. The primary purpose of Lighthouse is to help you optimize and improve the performance, accessibility, and SEO of your website or web app.

Benefits of Google Lighthouse Tool

Lighthouse speed test offers many benefits to its users. The primary benefits of the Lighthouse tool are mentioned below:

1. Accessed in Multiple Ways: You can access the Lighthouse report in four ways, i.e., using DevTools, Chrome extension, CLI, and Lighthouse API. You can use any of these methods as per your requirements to perform the Lighthouse page speed test.

2. Gives More Controls Over Your Data: Lighthouse gives you several filters to check the performance of your website. It allows you to have more control over connection speeds and limitations. Lighthouse lets you download the report in various forms and share it with your technical team to make the necessary improvements.

3. Multiple Pages can be Analyzed: With the Google Lighthouse page speed test, you can analyze multiple pages simultaneously, reducing the burden on you to repeat the same task. Lighthouse-CI Command can run multiple tests at once, quickly giving you an overview of the performance of various pages. You can use various Lighthouse page speed packages, such as the Lighthouse Parade and Lighthouse Batch packages, which offer more complex and customizable performance tests for more detailed analysis. Both packages allow you to test the performance of any number of URLs, giving you a comprehensive view of the performance of your website.

4. Easy to Use: Lighthouse is relatively easy to install & use. It requires minimal setup and allows users to configure the system with custom settings to meet their needs better. The user-friendly interface makes it easy to navigate and conduct audits of a website’s performance.

5. Provides Comprehensive Report: Lighthouse provides a comprehensive report on a website’s performance. It covers various topics such as accessibility, SEO, best practices, and more. The report also provides insights into how the website can be optimized with helpful recommendations.

How does Lighthouse measure Page Speed Performance?

Lighthouse page speed test collects data for the score computation using simulated navigation data (what Google refers to as "lab data," also known as synthetic data). Google keeps on updating the Lighthouse page speed test. In its most recent version, v10, five indicators, each with a distinct weight, are utilized to monitor loading speed:

Largest Contentful Paint (LCP): Lighthouse gives 25% weightage to this metric. LCP analyzes the display speed of the largest element on a web page.

Cumulative Layout Shift (CLS): It has a weightage of 25% in the performance score. It is a number that assesses a web page's visual stability.

Total Blocking Time (TBT): It has a weightage of 30% in the lighthouse speed test. It is an indication that collects the times when a page cannot respond to interactions based on the observation of Long Tasks (which need more than 50 ms to perform) in the Main Thread.

First Contentful Paint (FCP). FCP weighs 10%. It denotes when the browser renders the first element declared in the DOM. This measure eliminates iframes and examines rendering in a technical sense rather than how it appears to the user.

Speed Index (SI): The Speed Index measures the speed with which components in the viewport, or above the fold, are loaded. It weighed 10% in the lighthouse speed test.

Lighthouse metric weightage
Weightage Given by Lighthouse to Different Metrics

Lighthouse SEO report also provides suggestions for improvement, such as minimizing the size of resources or optimizing content for speed. You will see all of this data in the final Lighthouse audit report. You can then use the scores to make improvements and optimize the page.

What is Page Speed & Why is it Important?

The page speed index is a metric that Google uses to measure how quickly a website loads. Google uses the page speed index to determine if a website is user-friendly, relevant, helpful, and has good original content.

If your site has a high page speed index, Google will rank it higher in search results. If a site has a low page speed index, Google may downgrade it in search results, which might be less valuable for its users. 

The page speed index is calculated based on a few factors, including the load time of your page, the amount of HTTP requests on your page, the size of your page, and whether your page has any content that is not easy to crawl and readable by Googlebot

Therefore, you must optimize your page for speed to rank better in Google. Please read our guide on Google Page Speed Index.

How to Use Google Lighthouse?

Google Lighthouse performance metric calculates a series of individual tests that measure the loading performance of your web page. Each of these tests is evaluated and scored based on its performance.

Lighthouse combines the scores of all the individual tests to calculate the overall performance metric. It first normalizes the test scores to a scale of 0 to 100. Then, use these average test scores as the overall score.

In addition to the individual test scores, Lighthouse also looks at several other factors. These include the size of the page, the connection speed, the server response time, and other page optimization factors.

Access Lighthouse Report from Chrome Extension

Accessing a Lighthouse report for a web page provides visibility on how a web page performs and what areas may need improvement. Here is a quick guide on accessing a Lighthouse report for a web page:

1. Go to the Chrome web store and download the "Lighthouse" extension. The extension is free and easy to install.

2. Once installed, open the page that you want to audit.

3. Click on the "Lighthouse" icon in the Chrome browser.

4. Click "Generate Report" and wait a few moments. Currently, Lighthouse only generates the report for one page at a time.

5. The report will open in a new window. You can view the information, print it, or save it for later.

6. Use the report to identify areas that need improvement and make changes to the web page to improve performance and user experience.

Access Google Lighthouse from Chrome DevTools

Alternatively, you can run Lighthouse in Chrome DevTools. It offers the advantage of selecting the device (desktop/mobile) for which you want to generate a report. Follow these steps:

1. Open the page you want to audit.

2. Open Chrome Developer Tools. Right-click on the page and select "Inspect."

3. Select "Lighthouse" from the top menu.

4. You can now select the parameters you want to consider for your lighthouse report. The various options include

 a. Mode: Navigation (analyze page load), Timespan (start timespan for web page), or Snapshot (analyze page state). Read more about user flows in Lighthouse here.

 b. Select Device type: Desktop or Mobile

 c. Select what reports you want. By default, all five are selected (Performance, Accessibility, Best Practices, SEO, and PWA)

5. Finally, click the blue button on the top right corner, and Lighthouse will generate the report quickly.

Using Lighthouse to generate a report is a great way to learn how your web page performs, identify potential issues, and make necessary changes to improve the user experience. 

Now that we know how to access and generate a Lighthouse report, let us understand how to understand various Lighthouse recommendations.

Lighthouse for Page Performance Issues

Lighthouse evaluates different aspects of your website and provides helpful recommendations for improving its performance. The tool can identify the most significant issues slowing down your website. 

After running a Lighthouse audit, you can get detailed feedback on how to optimize your page. Besides identifying page load issues, it can also help you identify and fix coding issues that affect performance. It can detect problems related to HTML, JavaScript, and CSS and provide recommendations for improving them.

Here are some ways to address performance issues in Lighthouse:

1. Reduce page size

If your page is too big, users must wait for it to load. Ensure you're uploading smaller sizes and compressing images as much as possible. You can also optimize your code to reduce the page size.

2. Optimize your code

Your page's load time can be affected by the time it takes for your browser to parse and understand your code. You can optimize your code by minimizing the amount of your code and by writing clean, optimized code.

3. Improve your server response time

The time it takes a server to respond to a request can affect your page's load time. Use tools like Google Page Speed Insights or GTMetrix to analyze your server's performance and optimize where necessary.

4. Host your site on a fast server

Your server's speed can affect your page's load time. Host your website on a reliable, high-speed server to improve performance.

5. Use fewer resources

If your page uses too many different resources, it will take longer to load. Keep your page simple and avoid using too many unnecessary elements.

Lighthouse for Loading Issues

Page performance is mainly affected due to poor page loading. Google Lighthouse helps identify issues with the page load speed, the page size, and the load speed of resources on the page. It is important to note that Google Lighthouse can only audit static web pages, not pages that require user interaction.

Most of the solutions listed in the previous section can help fix your page loading issues. Page loading can be challenging to curb under some circumstances. Here are some common loading issues you'll want to address:

1. Your page loads too many resources - You may use too many different elements, such as scripts and images. You want to keep your page simple and avoid using too many unnecessary elements.

2. Your page uses too much bandwidth - Hosting your site on a fast server isn't enough. You also need to make sure you're using only a little bandwidth. Avoid immediately streaming videos and high-resolution images that can bog down your page. You can instead lazy-load photos and videos.

3. Your page is not accessible to Googlebot - If Googlebot can't crawl your page, it won't be able to index it in search results. Make sure your page is accessible to Googlebot by following SEO best practices.

Why Improving Page Speed with Lighthouse is Difficult?

Page speed is an important metric to consider when launching a website and is crucial for improving the user experience. A slow site can lead to lower traffic and conversion rates. Therefore, optimizing a website to run as quickly as possible is essential. 

Improving page speed with Google Lighthouse is an important step in SEO optimization. It's a tool that tests a page's performance and gives feedback on how to make it run faster. But it can be challenging to fix page speed issues. Google Lighthouse only offers page-by-page optimization, which can be difficult for web admins with a big site. 

Reviewing each page and making the suggested changes can be long and tedious. It is especially difficult for e-commerce stores or B2B sites that have a large number of pages. Not only does it take a lot of time, but it also requires a certain amount of technical knowledge to implement the suggested changes successfully.

Additionally, it's challenging to know which pages need optimization. It is not enough to focus all efforts on the home page. Some pages can be more important than others, so knowing which pages are underperforming is essential. 

Lastly, page speed optimization is a continual process. Optimizing once does not guarantee it will stay that way. Websites are constantly changing, so it is vital to monitor for page speed issues continually. Web admins must be aware of changes to a web page's content and how they can adversely affect page speed. Thus, web developers, content editors, and SEO experts must work together to ensure changes in one element do not negatively impact the other.

Improving page speed with Google Lighthouse is a difficult task. It is more than just going through each page and applying the suggested changes. Understanding which pages are essential and ensuring they load quickly is also important.

It is essential to make sure the website is constantly being monitored and optimized to make sure it's performing optimally.

Optimizing Page Speed Issues Across Website & at Enterprise Scale

Page speed is one of the most important considerations when launching a website. It is essential for a good user experience and can significantly impact traffic and conversion rates. Search engines like Google highlight the importance of page speed and user experience optimization. Both are critical ranking factors that Google considers when ranking your web pages on SERPs.

Enterprise websites, in particular, need a way to optimize page speed across the entire website efficiently. Here's how they can accomplish this.

Understanding Page Speed Issues at Enterprise Scale

The first step in optimizing page speed at an enterprise scale is understanding the issues. Big websites have many pages, and it can be challenging to identify the most important ones. Tools like Google Analytics can assist in some way. They offer insights into how long each page takes to load and which ones are the slowest. Similarly, Google Lighthouse reports can help further diagnose the problem and highlight the reasons for slow page loading.

The next step is to create an optimization strategy. A good plan will prioritize which pages need to be optimized first and then focus on the least important pages. It's also essential to monitor the website after optimization to ensure any new changes don't adversely affect page speed.

Why do Enterprises Need a Specialized Page Speed Optimization Tool?

Optimizing page speed at an enterprise scale can be difficult and time-consuming. Both Google Analytics and Lighthouse offer only page-by-page optimization. It also leaves scope for much manual work.

It is not feasible for a million-page domain to manually look through each page and make the suggested changes. It is also challenging to prioritize which pages to work on first. Should you prioritize pages with slow loading? Or focus on high-traffic pages with sub-par scores?

As such, enterprises need a specialized tool to help them optimize page speed at scale. A tool like Quattr can be beneficial in this regard. It uses Google Lighthouse reports to test page speed and gives a prioritized list of recommendations. Web admins can also correlate page speed issues with specific business metrics like clicks and market share. Thus you know how a slow page impacts your web traffic and which pages to optimize for page speed.

How Can Quattr Help Improve Page Speed at Scale?

Quattr is a powerful tool for enterprise websites looking to optimize page speed at scale. It comprehensively analyzes a website's performance and provides detailed recommendations for making it run faster. 

Quattr uses AI and advanced analytics data from sources such as Lighthouse, Google Search Console, and other sources to create a single SEO Data Lake. It establishes your personalized growth data lake that includes data from a website and its top competitors, scoring based on performance and user experience. 

With these capabilities, the platform generates an actionable ranked list of page speed and user experience recommendations. You can use the list to improve page experience across the entire site.

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

You can easily correlate the recommendation with business metrics like organic traffic or conversion value. You can also compare your page speed scores with top competing pages and benchmark scores against your SERP competitors.

compare page speed & other ranking factors with competitors in Quattr
Quattr allows you to compare ranking factors with top SERP competitors

Quattr also offers an easy-to-follow workflow. It guides web admins through page optimization, helping them make the suggested changes quickly and efficiently. The platform continuously monitors and suggests improvements for page speed across the entire website.

Regularly Optimize for Lighthouse Page Speed

A slow website can negatively affect your business and cause you to lose potential customers. Luckily, there are ways you can improve the speed of your website, such as the Google Lighthouse speed test. 

Using the Google Lighthouse page speed test, you can instantly check the performance of your website. This free tool can help explain why your web pages are loading slowly. It also suggests steps improve your page speed scores and optimize for user experience.

However, optimizing page speed using the Lighthouse page speed test is time-consuming when you have multiple pages to work on. Manually optimizing each page’s page speed across a large B2B/B2C website can be challenging, and enterprises must recognize the value of optimizing their website for page speed. 

SEO platforms like Quattr can be helpful in situations where you want to check the performance of multiple pages in one go. Quattr features offer you various controls, provide an in-depth analysis of page speed issues, and provide a streamlined workflow for improvement.

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Lighthouse Page Speed Optimization FAQs

What is Lighthouse Page Speed?

Lighthouse Page Speed is an open-source tool that evaluates webpages' performance and finds ways to improve their speed. It generates a report based on current page performance, offering insights and suggestions for improvement. It tests the performance of both desktop and mobile versions of web pages.

What can you check with Lighthouse?

With Lighthouse, you can check and assess several aspects of your website or web apps, such as performance, accessibility, SEO, best practices, and Progressive Web App (PWA) features. It can also check your code for common web development mistakes and identify potential security vulnerabilities.

What is the difference between Google Lighthouse & Page Speed Insights?

The main difference between Google Lighthouse and Page Speed Insights is that the Lighthouse auditing tool is far more comprehensive, providing more detailed and accurate information on the website's performance.

Does Google Lighthouse score affect SEO?

Google Lighthouse score is not the only factor that affects your website's SEO. Many factors, such as content quality, page structure, page loading speed, and backlinks, determine SEO. However, a high Google Lighthouse score indicates a well-structured, optimized website and can positively impact SEO indirectly.

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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