How a Google Lighthouse Report Can Help Improve Website Speed

You’ve launched your website and put your heart into it. It looks great, it sounds like you, everything’s in place. But it still feels sluggish and people aren’t sticking around.

Here’s the good news. You can get answers in less than 30 seconds using a free Google Lighthouse report. This blog will break down what it is and how to use it to implement real improvements. No jargon. No panic. Just practical help that makes your website faster and your user experience better.

What is Google Lighthouse? 

Google Lighthouse is a free website audit tool that checks how well your website is performing. It looks at things like:

• How fast your site loads
• Whether it’s mobile friendly  
• If it meets best practice guidelines 
• How easily Google can crawl it 

A Google Lighthouse report will give you a score out of 100, tells you what’s slowing down your website and offers suggestions so you can improve these aspects. 

Think of it like a website health check that you can run yourself anytime, no developer needed. 

For a full rundown on Google Lighthouse, read Google’s overview here.

Why does this Matter? 

A slow website can seriously hurt your sales. Most people won’t wait more than 3 seconds for a page to load, they’ll just leave.

Website speed can impact how well you show up in search engines too. Google takes site speed into account when ranking pages.

So, whether you’re a web developer or website owner, a Google Lighthouse report can help improve your website’s overall experience and performance to boost online visibility and competitiveness. 

How does Google Lighthouse Work? 

Google Lighthouse performs an audit for five main website optimisation categories. These are: 

1. Performance 

This measures how a website performs in terms of how quickly a website loads and how quickly users can access it. 

Website performance is established based on five metrics:

• First contentful Paint (FCP): This is the time needed for the first image or text to become visible. 
• Largest Contentful Paint (LCP): The time needed for the largest element to load. 
• Total Blocking Time: The amount of time a page doesn’t react to user input
• Cumulative Layout Shift: Measures visual stability of a webpage 
• Speed Index: How quickly page content loads 

2. Accessibility 

This evaluates how user-friendly and accessible your website is, especially for users with visual impairments. For example, it checks images to see if the alt text is specified. 

3. Best Practices 

This checks if your website is built using modern standards of web development. This can include: 

• Having valid source maps 
• Images having the correct aspect ratio 
• JavaScript libraries being safe from any vulnerabilities 
• Website is free from page errors 

4. SEO 

Google Lighthouse also checks how technically optimised your website is. This can include:

• Internal links being crawlable 
• Having a mobile-friendly website 
• Metadata presence 
• Having suitable alt texts 

To learn more about technical SEO, read our blog on “What is Technical SEO and Is It Holding Back Your Website?”.

5. Progressive Web Apps (PWA) 

This evaluates your website’s ability to offer app-like experiences on desktops or mobile devices. It evaluates if your website: 

• Is fast and reliable on mobile network and can be used offline 
• Is installable on multiple devices and offers push notifications 
• Is PWA-optimised based on best practices 

Your Google Lighthouse report will give you a score out of 100 for each of these categories, except for PWA where you will receive a badge instead. 

How to Run a Google Lighthouse Report 

1. Navigate to your website on Chrome. 
2. Right-click on the page and select “Inspect”.
3. Click the Lighthouse tab on the top, which is found in the >> icon. 
4. Choose “Performance” (or tick other boxes if you want a deeper dive).
5. Click “Analyse page load” and let it run.
6. Done! You’ll get a report showing your scores, plus a list of suggested fixes.

Turning Your Google Lighthouse Report Into Real Results 

So, we can use Google Lighthouse to understand how well our website is functioning, and specifically to check website speed using the performance score. 

A “good” performance score is usually 90+, suggesting your page is well-optimised with a fast loading speed. If you’re in the red (under 50), don’t stress. This just means there’s room for improvement. In this case, you can implement Google’s Lighthouse suggestions to improve your website performance and speed. 

To help you get started, here are 3 common speed issues and how to fix them: 

1. Your Images Are Slowing You Down

Large images are one of the biggest culprits. To fix this, you should use .webP rather than .jpg or .png. Tools like Sqoosh or Smush can compress your images for you. 

On Shopify? Use a plugin like WEBP Image Optimiser

You want your images to look great and load fast and yes, you can have both. This can significantly boost your performance score on your Google Lighthouse report.

2. You’re Not Lazy Loading Your Images

Lazy loading is when images load when someone scrolls to them. 

Most builders (like Shopify or WordPress) will already support this. You might just need to turn it on in your theme or settings.  This one tweak can make a big difference to how fast your page feels.

3. You’re Using Too Many Plugins or Add-ons

If you’ve added lots of features over time (especially on WordPress), some of them might be dragging your speed down.

To fix this, you should: 

• Remove anything you’re not using
• Swap bulky plugins for lighter alternatives
• Ask your developer to do a plugin audit

Think of it like decluttering. Your site will feel faster and cleaner.

Summary 

A faster website isn’t just about a better SEO or better Google Lighthouse report scores. It also builds trust.

If someone clicks your link and the page loads instantly, they’re more likely to stick around. More likely to browse. More likely to buy.

So yes, Lighthouse is a great tool. But what it’s really helping you do?

It’s helps you to understand issues on your website. You have a checklist of what you can improve. Once these improvements are in place you build a better experience for your clients. And that’s what really moves the needle.

Still need help with your SEO or interpreting your Google Lighthouse report? We’re an expert technical SEO Agency based in Birmingham who work with clients across the UK. Get in contact today for expert technical SEO support.  

FAQ’s

What is a Google Lighthouse report?

Google Lighthouse is a free, automated tool which provides insights into a sites performance and overall experience. It generates a detailed report and scores on performance, accessibility, best practices, SEO and progressive web apps. Accordingly, lighthouse provides recommendations to help improve your website.

What are the benefits of Google Lighthouse?

Lighthouse is a useful tool for measuring site performance across five important metrics so that you can identify which areas need the most attention. You can use data from the Google Lighthouse report to optimise your website and SEO. This will improve user experience, boost your online rankings and drive conversions.

What is the speed index in Google Lighthouse?

Speed index measures how quickly your website content loads onto the page. Google Lighthouse will calculate your page’s speed index by recording the page loading in the browser and computing the visual progression between frames.

What is a good Lighthouse score?

Lighthouse scores of 90 and above suggest that your website is performing well in terms of performance, accessibility, best practices and more. Scores between 50-89 suggests there are areas for improvement, while scores below 50 suggests website quality is poor with significant room for improvement.

How important is the Lighthouse score?

A high Lighthouse score can be very important for the success of your website. Google’s Lighthouse report highlights areas of improvement for your websites performance, accessibility, best practices and SEO. Using this feedback can support you in creating a high-quality website. This increases your odds of ranking higher in search engine results and driving organic traffic to your website.