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How To Test Your Website Speed With Google Lighthouse

In today’s digital landscape, website speed is a critical factor in user experience and overall success. Google Lighthouse, an automated website analysis tool developed by Google, provides website owners and developers with comprehensive insights into performance, accessibility, best practices, and search engine optimization.

This article offers practical guidance on testing website speed with Lighthouse, including tips for improving performance scores and troubleshooting common issues.

By harnessing the power of Lighthouse, you can ensure a fast and seamless user experience, leading to enhanced customer satisfaction and improved business outcomes.

Understanding Lighthouse Scores

The Lighthouse scores provide a comprehensive evaluation of a website’s performance, accessibility, best practices, and SEO, ranging from 0 to 100, with 100 being a perfect score. These scores are important for understanding the overall health of a website and identifying areas for improvement.

Lighthouse metrics can be compared to Google’s Core Web Vitals to assess user experience.

Analyzing waterfall visualization can provide insights into performance metrics.

Tools like DebugBear and PageSpeed Insights can be used to analyze and optimize Lighthouse scores.

Running a Lighthouse Test

To run a Lighthouse test, you can use online tools like Google PageSpeed Insights or DebugBear Speed Test. Here’s how to do it:

  1. Enter your website URL into the tool of your choice.
  2. Review the Lighthouse Performance score, aiming for a score of 90 or higher.
  3. Analyze the waterfall visualization to understand resource loading and content appearance.
  4. Optimize third-party code, implement Lighthouse recommendations, and compare Lighthouse scores with Core Web Vitals to troubleshoot any discrepancies.

Interpreting Lighthouse Performance Metrics

An important step in evaluating your website’s performance is to interpret the Lighthouse performance metrics.

To understand your website’s performance, you can start by analyzing the waterfall visualization, which shows resource loading and content appearance.

Additionally, troubleshooting Lighthouse scores can involve comparing them with Google’s Core Web Vitals, as Lighthouse metrics represent the slowest user experiences.

Debugging Lighthouse performance involves identifying factors that may affect the scores, such as random variation and different content.

Interpreting Lighthouse recommendations can guide optimization efforts to improve performance.

Reliability of Lighthouse Data

Using different operating modes and simulated throttling, Lighthouse data can sometimes be inconsistent, but it is still a valuable tool for evaluating website performance.

Here are some key points to consider regarding the reliability of Lighthouse data:

  1. Lighthouse data limitations: Lighthouse uses simulated network conditions that may not accurately represent real-world user experiences, resulting in lower scores compared to Core Web Vitals.
  2. Lighthouse vs Core Web Vitals: Lighthouse metrics represent the slowest 5-10% of user experiences, while Core Web Vitals are based on the 75th percentile, leading to differences in reported metrics.
  3. Lighthouse score fluctuations: Lighthouse scores may vary between runs due to factors like random variation, different content, and background activity, making direct comparisons challenging.
  4. Comparing Lighthouse scores and server performance: Comparing Lighthouse scores collected in different environments may not be directly comparable due to variations in server performance and location.

Using DebugBear for Accurate Testing

However, DebugBear provides a more reliable and accurate method for testing website speed.

DebugBear offers features such as device and network configuration options, detailed analysis, and score regression alerts.

Unlike PageSpeed Insights and Lighthouse, DebugBear collects metrics directly in a throttled environment, ensuring reliable test results.

DebugBear also allows for the selection of the Mobile Fast config, which runs a lab test with settings similar to real users.

Strategies to Improve Lighthouse Performance Score

What are some effective strategies to improve your Lighthouse Performance score?

Here are four strategies you can implement:

  1. Remove unnecessary third-party code: Reduce the number of external scripts and plugins on your website to minimize their impact on performance.
  2. Optimize images: Compress and resize images to reduce their file size without sacrificing quality. This helps improve page load times.
  3. Reduce server response time: Optimize your server configuration and code to ensure fast and efficient responses to user requests.
  4. Leverage browser caching and minify CSS and JavaScript: Use caching techniques to store static resources on the user’s browser and minimize the size of your CSS and JavaScript files for faster loading.

Enhancing User Experience With Lighthouse

Optimizing for slower mobile devices and worse internet connections can enhance user experience with Lighthouse. By simulating network conditions and using real user data, Lighthouse provides valuable insights for performance optimization. Additionally, the waterfall visualization allows for a detailed analysis of resource loading and content appearance.

Lighthouse also offers customization options, allowing developers to tailor the testing environment to match real user conditions. Overall, Lighthouse empowers website owners to improve user experience by optimizing their website’s speed and performance.

Key FeaturesBenefits
Network SimulationReplicates slower internet speeds
Real User DataProvides insights into user experience
Waterfall VisualizationAnalyzes resource loading and appearance

Troubleshooting Lighthouse Test Results

When encountering discrepancies in Lighthouse test results, website owners can troubleshoot potential issues to ensure accurate performance evaluation. Here are some common issues with Lighthouse metrics:

  1. Comparing Lighthouse scores across different websites may not be directly comparable due to varying server performance and location.
  2. Troubleshooting Lighthouse errors and warnings can help identify specific issues causing performance problems.
  3. Optimizing website performance based on Lighthouse recommendations can lead to improved scores.
  4. Understanding the impact of third-party scripts on Lighthouse scores can help prioritize their optimization.


In conclusion, Google Lighthouse is a valuable tool for testing and improving website speed.

By utilizing Lighthouse, website owners and developers can gain insights into their website’s performance and make necessary optimizations.

Additionally, the reliability of Lighthouse data can be enhanced by using tools like DebugBear.

Ultimately, improving Lighthouse performance scores can lead to a better user experience and drive better business outcomes.

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