How to Use Google Lighthouse for Website Performance Analysis

ella | Posted on 25 April 2025 |

In the digital space, speed and user experience are everything. You can have a beautiful website, but if it takes too long to load, your audience won’t stick around. Slow websites drive users away, and this can hurt your business or content reach. That’s where Google Lighthouse comes in. This tool is designed to assess the performance of your website, helping you spot issues and make improvements that can drive better user engagement.

Google Lighthouse isn’t just for developers—it’s for anyone who cares about a website’s health. It’s easy to use and provides clear feedback on what’s working and what needs attention. But to get the most out of it, you need to understand how to use it properly. This blog will guide you through the steps of running performance analysis with Google Lighthouse and explain how you can take actionable insights from its reports to boost your website’s performance.

What Is Google Lighthouse?

Before jumping into how you can use Google Lighthouse for performance analysis, let’s briefly discuss what it is. Google Lighthouse is an open-source tool that audits a website’s performance. It runs audits on key aspects like performance, accessibility, SEO, best practices, and Progressive Web App (PWA) compatibility. The tool gives your website a score, along with recommendations for improving areas that might be holding back performance.

Google Lighthouse is particularly helpful because it generates a comprehensive report, offering insights into how a website is performing on both desktop and mobile devices. It also provides actionable suggestions that anyone can follow, even if you’re not a technical expert.

How to Run a Google Lighthouse Audit

Getting started with Google Lighthouse is straightforward, and you don’t need to be a technical expert to run the tool. Here’s how to use it to analyze your website’s performance:

Accessing Google Lighthouse

You can access Google Lighthouse through the Chrome DevTools. Here’s how you can do it:

Open your website in Google Chrome.
Right-click anywhere on the page and select Inspect or press Ctrl + Shift + I (Windows) or Cmd + Option + I (Mac).
Once the DevTools window opens, click on the Lighthouse tab.
Choose the type of report you want to generate (Desktop, Mobile).
Click the Generate report button.

The tool will now run an audit, testing various aspects of your website’s performance. Depending on the size of the site, the audit can take anywhere from a few seconds to a couple of minutes to complete.

What Lighthouse Measures

Google Lighthouse evaluates websites across several performance categories:

Performance: This measures the speed and responsiveness of your site.
Accessibility: This checks how accessible your site is for people with disabilities.
SEO: This assesses how well your site is optimized for search engines.
Best Practices: This evaluates whether your website follows best practices for security and reliability.
PWA: This checks if your site follows Progressive Web App guidelines for offline use and mobile-friendliness.

Once the audit is complete, Lighthouse provides a detailed report with scores in each of these categories.

Analyzing the Performance Report

After the audit is done, you’ll get a performance score that reflects how well your site is doing in terms of speed and responsiveness. The performance section breaks down key performance metrics that directly impact the user experience.

Key Metrics in the Performance Section

First Contentful Paint (FCP): Measures how long it takes for the first piece of content to appear on the screen.
Largest Contentful Paint (LCP): This measures how long it takes for the largest piece of content to load on the page.
Total Blocking Time (TBT): This measures how long the browser is blocked from responding to user input.
Cumulative Layout Shift (CLS): This measures visual stability by tracking unexpected shifts in the page layout as it loads.
Time to Interactive (TTI): This measures how long it takes for the page to become fully interactive, allowing users to engage with it.

How to Improve Your Performance Score

The performance section of the Lighthouse report also includes suggestions on how to improve each of the metrics. These might include things like optimizing images, reducing JavaScript execution, or improving server response times. Some of the most common recommendations include:

Image Optimization: Large image files can slow down your website. Lighthouse may recommend compressing or resizing images to reduce load times.
JavaScript Optimization: Too much JavaScript can block rendering and delay user interaction. Consider deferring or reducing JavaScript execution.
Minimizing CSS and HTML: Reducing the size of CSS and HTML files can help improve load times.
Lazy Loading: Implementing lazy loading for images and other media can improve load time by only loading content when it is visible on the user’s screen.

How to Use Google Lighthouse for SEO

Google Lighthouse also runs an SEO audit to help you determine how search-friendly your website is. This audit covers several factors related to search engine optimization, including the use of proper HTML tags, mobile-friendliness, and URL accessibility. While Lighthouse doesn’t replace Google’s Search Console, it is still a great tool for checking the basics of your website’s SEO health.

Key SEO Metrics in Lighthouse

Meta Tags: Lighthouse checks whether your website has relevant meta tags, such as the title tag and meta description. These are essential for search engines and users alike.
Mobile-Friendliness: With Google focusing on mobile-first indexing, Lighthouse assesses if your site is responsive and performs well on mobile devices.
HTTPS Security: Google prefers websites that are secure, and Lighthouse will check if your website uses HTTPS.
Heading Structure: Properly structured headings (H1, H2, etc.) are crucial for both accessibility and SEO. Lighthouse ensures your headings are used correctly.

SEO Recommendations from Lighthouse

Lighthouse will provide actionable suggestions on how to improve your SEO score. For example:

Improving Title Tags: Lighthouse might point out that your title tags are too long, too short, or missing altogether.
Missing Alt Text for Images: If you have images without alt text, Lighthouse will flag this and recommend adding descriptive alt attributes for accessibility and SEO.
Mobile Usability: If your website isn’t mobile-friendly, Lighthouse will point this out and recommend ways to improve it, like using responsive design.

Best Practices and Accessibility Reports

Beyond performance and SEO, Google Lighthouse also evaluates best practices and accessibility on your website.

Best Practices

This section evaluates whether your website follows modern web development standards. It checks for things like secure HTTPS connections, valid JavaScript, and the correct use of APIs.

Common issues that might come up include:

Missing HTTPS: If your site isn’t using a secure connection, Lighthouse will flag it as a security issue.
Using Deprecated APIs: If you’re using outdated or deprecated APIs, Lighthouse will suggest updating them.
Using JavaScript libraries with known vulnerabilities: Lighthouse may recommend updating your JavaScript libraries to the latest versions for security purposes.

Accessibility

Accessibility is a vital part of modern web development. Lighthouse checks whether your site is usable by people with disabilities, including users who rely on screen readers or keyboard navigation.

Some common accessibility issues include:

Poor color contrast: Lighthouse checks if there’s enough contrast between text and background colors for visually impaired users.
Missing ARIA attributes: ARIA (Accessible Rich Internet Applications) attributes help improve the user experience for people with disabilities. If they’re missing, Lighthouse will suggest adding them.
Keyboard accessibility: Lighthouse ensures that your site is navigable using a keyboard, which is crucial for users with mobility impairments.

Making the Most of Your Lighthouse Reports

Once you’ve run a Lighthouse audit and reviewed the results, it’s time to take action. Use the feedback from the tool to prioritize improvements on your website. Here’s how to make the most of the Lighthouse report:

Prioritize Issues Based on Impact

Lighthouse provides a list of issues along with their severity. Focus on fixing high-impact issues first—things that are slowing down your site or affecting user experience. For example, improving page load speed and addressing accessibility problems should be top priorities.

Monitor Your Progress

After making changes, run another Lighthouse audit to see if your improvements have worked. You should see your performance score improve, along with other metrics like accessibility and SEO scores. This process is iterative—continue to make adjustments and keep an eye on how your site is performing.

Final Thoughts

Using Google Lighthouse for website performance analysis is a straightforward way to ensure your site meets modern standards in terms of speed, SEO, accessibility, and security. By running regular audits, you can stay on top of potential issues and make informed decisions to improve your site’s user experience and ranking. It’s a valuable tool for anyone looking to enhance their website’s overall health.