A Beginner’s Guide to Using the Lighthouse Tab in Developer Tools


A Beginner’s Guide to Using the Lighthouse Tab

If you’re a beginner in web development, optimizing the performance and quality of your website is crucial. The Lighthouse tab in the browser’s Developer Tools provides a comprehensive set of tools to assess and improve various aspects of your web page. In this guide, we will explore how novices can effectively use the Lighthouse tab with practical examples.

Accessing the Lighthouse Tab

To access the Lighthouse tab, follow these steps:

  1. In Google Chrome, Firefox, or Microsoft Edge, open the Developer Tools using the shortcut Ctrl + Shift + I (Windows) or Cmd + Option + I (Mac).
  2. Click on the “Lighthouse” tab in the Developer Tools panel.

Running a Lighthouse Audit

Once you have accessed the Lighthouse tab, you can run an audit to evaluate your web page’s performance, accessibility, best practices, and more. Here’s how to run a Lighthouse audit:

  1. Make sure the “Performance” checkbox is selected. You can also choose to include other categories like “Accessibility,” “Best Practices,” and “SEO” if desired.
  2. Click on the “Generate report” or “Run audits” button to start the audit process.
  3. The Lighthouse tool will analyze your web page and generate a detailed report with scores and recommendations for improvement.

Interpreting the Lighthouse Report

The Lighthouse report provides valuable insights into your web page’s performance and offers suggestions for optimization. Here are some key elements to understand:

1. Performance Score

The performance score represents how well your web page performs in terms of speed and loading times. It is measured on a scale of 0 to 100, with higher scores indicating better performance.

2. Performance Opportunities

This section highlights specific opportunities to improve your web page’s performance. It identifies areas where optimizations can be made, such as reducing server response times, minimizing render-blocking resources, or optimizing image sizes.

3. Diagnostics

The diagnostics section provides additional information and suggestions for improving your web page. It may include recommendations for addressing issues related to accessibility, SEO, or best practices.

4. Passed Audits

Under the “Passed audits” section, you can find a list of audits that your web page has successfully passed. These audits assess various aspects of your website and provide assurance that you are following best practices.

Implementing Recommendations

After reviewing the Lighthouse report, it’s time to implement the recommendations to enhance your web page’s performance and quality. Here are some general tips:

  • Start by addressing the high-impact opportunities suggested in the report. These improvements can have a significant impact on your website’s overall performance.
  • Pay attention to performance optimizations, such as optimizing images, minifying CSS and JavaScript files, and leveraging browser caching.
  • Ensure your web page meets accessibility standards by addressing any accessibility-related recommendations.
  • Follow the best practices suggested in the report, such as using proper HTML structure, optimizing CSS and JavaScript delivery, and implementing responsive design.
  • Consider the SEO recommendations and make necessary changes to improve your web page’s visibility in search engine results.

Remember to re-run the Lighthouse audit after implementing the recommendations to track your progress and identify further areas of improvement.


The Lighthouse tab in Developer Tools is a powerful tool for assessing and optimizing the performance and quality of your web page. By running audits, interpreting the reports, and implementing the recommendations, you can enhance your website’s performance, accessibility, best practices, and SEO. With practice and continuous improvement, you can create high-quality web experiences for your users. Happy optimizing!