Tracking your site’s performance is crucial. It can help you identify weak areas and take the necessary steps to improve them. However, you might feel torn between two popular performance-monitoring tools: PageSpeed Insights vs Lighthouse.
Fortunately, we’ve put together a guide to help you make a decision. By looking at how these two tools fare in different areas, you should be able to select the one that best meets your needs.
Overall, the tools share a lot of similarities. It’s because PageSpeed Insights’ performance testing engine is based on Lighthouse.
However, there are also some key differences between the tools and each gives you access to different information, despite the performance part being based on the same engine.
In short, PageSpeed Insights presents the Lighthouse data in a different way. It also gives you access to data beyond the Lighthouse analysis, such as real user data from the Chrome User Experience Report. At the same time, Lighthouse also presents some data that PageSpeed Insights doesn’t include, such as reports on SEO and accessibility.
👉 In this post, we’ll compare PageSpeed Insights vs Lighthouse across three key features. We’ll also share some tips to help you choose the right tool for your website. Let’s get started!
📚 Table of contents:
- How do you run a test? Ease of use
- Where does the data come from?
- What reports and metrics can you access?
PageSpeed Insights vs Lighthouse: Three key features compared
Lighthouse is an open-source auditing tool created by Google that comes built into Chrome and most other Chromium-based browsers. PageSpeed Insights is also a Google tool and can be accessed on any browser.
Let’s take a closer look at 🔎 these two online tools and how they compare in different areas:
1. How do you run a test? Ease of use
If you plan to run regular speed tests, you’ll want a user-friendly tool ⚙️ with an intuitive interface. In this section, we’ll compare PageSpeed Insights vs Lighthouse for ease of use:
PageSpeed Insights is relatively easy to use. To get started, simply enter your URL into the box and hit Analyze:
It will then generate two reports: one for your desktop site and one for the mobile version. You can click on either tab to view your performance on these devices:
The tool will instantly tell you whether you’ve passed or failed your Core Web Vitals test (assuming your site is receiving enough traffic to be included in the Chrome User Experience Report – more on that in a second).
PSI also breaks down each metric to demonstrate how your site performs in specific areas. We’ll take a closer look at these metrics and what they mean later in the post.
If you scroll down, you should see an overall performance score:
Anything above 90 indicates a fast-loading site. An orange score (50-89) means that your page has relatively good loading times, but you may need to make adjustments to improve its performance. Finally, a red score (anything below 49) means that your site takes a long time to load on this device, and you’ll need to do a bit more work.
Once again, you’ll receive a breakdown of the metrics on which the performance score is based. You’ll also get easy access to diagnostics and suggestions for improving each metric (we’ll talk more about these later).
Now, let’s turn to Lighthouse. As mentioned earlier, this tool was also created by Google, so you might notice some similarities.
To access Lighthouse, open Chrome and press the F12 key to launch the Developer tools:
Then, click on the tab with two arrows and select Lighthouse:
Next, you’ll be asked to select some options for your report:
👉 For example, you might choose to check your site’s accessibility or search engine optimization (SEO) only. You can also select the device you want to test your site on. When you’re ready, click on Analyze page load.
Lighthouse will then generate a report based on your selected categories. You’ll see a score for each area:
You can click on any category for a more detailed report:
If you select Performance, you’ll notice that the report is similar to the one generated by PageSpeed Insights. Again, this is because PSI uses Lighthouse as its analysis engine:
You’ll get a score for each Core Web Vitals metric, plus a list of suggestions for improvement. Depending on your performance, you’ll also find tips for other categories, including SEO and Best Practices.
Lighthouse lets you save a copy of your report. To do this, click on the three dots near the top and select your preference:
As you may have noticed, Lighthouse requires a bit more user input. Also, you’ll need to run separate tests for your desktop and mobile sites, whereas PageSpeed Insights lets you compare both reports with minimal effort.
2. Where does the data come from?
The available data sources 💾 are one of the biggest differences between PageSpeed Insights vs Lighthouse.
PageSpeed Insights offers two types of data:
- Field data – this is real data collected from your site’s real human visitors. It’s based on the Chrome User Experience Report. ⚠ Note – this data is only available if your site has enough traffic to be included in the report. If you just launched your site, you probably won’t be able to see any field data.
- Lab data – this is simulated data based on Lighthouse. It uses simulated test conditions such as a certain connection speed, visit location, and device.
Lab data is collected in a controlled environment and can therefore be helpful for troubleshooting performance issues:
One downside of PageSpeed Insights’ lab data is that you can’t adjust the connection speeds/throttling – you have to use Google’s configuration. If you run Lighthouse yourself, you can customize the configuration speeds.
Meanwhile, field data uses real-world performance metrics. That means it’s based on the experience of users who visited your site over the last 28 days:
This real-world data is based on the Chrome User Experience Report and can provide different results than lab data. Plus, the scores provided by field data might be more representative of your site’s performance because they’re calculated with real-world conditions.
With Lighthouse, you only get access to the lab data results. Because PSI is based on Lighthouse, that means you should get similar performance results from both tools when it comes to lab data.
However, one advantage of using Lighthouse for lab data is that you get more control over connection speeds and throttling. So if you want to play around with your site’s performance in different connection speed scenarios, that might make Lighthouse a better option.
3. What reports and metrics can you access?
Finally, we’ll evaluate PageSpeed Insights vs Lighthouse according to the reports 📊 generated by each tool. After all, this information demonstrates the usefulness of each tool for optimizing your website:
With PageSpeed Insights, you can analyze your site’s Core Web Vitals. These are a set of metrics that Google uses to evaluate your site’s performance and user experience.
Some of the key 🗝️ metrics include:
- Largest Contentful Paint (LCP): The time it takes for a page to fully load the largest item on the screen.
- First Input Delay (FID): The time your site takes to respond after a user interacts with it.
- Cumulative Layout Shift (CLS): To what degree elements on the page shift around as it loads.
For each metric, you’ll get a list of diagnostics, plus opportunities for improvement (depending on your score in that area):
👉 For example, if you have a poor LCP score, PSI might suggest removing plugins that load unnecessary CSS. Remember that these audits are pulled from Lighthouse.
As seen earlier, Lighthouse enables you to test different aspects of your site, including Performance, Accessibility, and SEO. The Performance report is based on your Core Web Vitals score and is identical to the PSI report.
Meanwhile, the Accessibility report can help you make your site more accessible. For instance, it will let you know if you have images that are missing alt text or if there isn’t enough contrast between your background and foreground elements:
The Best Practices report checks the overall health of your site’s code. It can identify security vulnerabilities and other issues that affect the user experience:
With Lighthouse, you can also test your site’s SEO best practice implementation:
The tool will highlight critical issues such as missing meta descriptions, an invalid robots.txt file, and illegible font sizes. Lighthouse will also list any links on your site without descriptive text.
By following these SEO tips, you can make your site more mobile-friendly and ensure that search engines can crawl and index your pages.
How to choose the right tool for your needs
As we have seen, PageSpeed Insights and Lighthouse are two similar tools that provide helpful insights into your site’s performance. As such, it can be challenging to decide which one to use for your website.
Overall, PageSpeed Insights is a more user-friendly tool. It focuses on your Core Web Vitals scores, which are Google ranking factors. You can also use PSI to test your site speed and user experience and follow the tool’s suggestions to improve your overall performance (and hopefully your rankings, too).
Meanwhile, Lighthouse provides additional insights into your site’s structure and lets you customize the connection speeds. This extra data makes it a popular option among web developers because it can help them identify problems with the code.
If you’re using a responsive WordPress theme or page builder, then you probably won’t need an advanced tool like Lighthouse to test your site’s performance.
However, if you’ve coded your own website or made a lot of customizations to the theme, Lighthouse can help you identify any accessibility or SEO issues that you may have overlooked.
Monitoring your site’s performance can help you improve the user experience and get more traffic. PageSpeed Insights and Lighthouse are two popular tools that you can use to track metrics such as Largest Contentful Paint and First Input Delay.
PSI is a user-friendly, web-based tool that lets you quickly check your site’s performance and compare the results on desktop and mobile devices. In addition to simulated lab tests based on Lighthouse, it also lets you see real-world performance data from Chrome users (assuming your site has enough traffic).
However, if you’re looking for deeper insights, Lighthouse is a better option. This tool is primarily used by web developers and also provides information about your site’s accessibility, SEO, and other best practices.
Do you have any questions about PageSpeed Insights vs Lighthouse? Let us know in the comments section below!