Why you should improve your Google Lighthouse Score

on 15th January 2021

(Last updated 5th July 2023)

Why Google Lighthouse?

There are many tools for auditing a website’s build quality but there is a simple reason why Liquid Light pays so much attention to Lighthouse – Google have a 91% share of the search engine market.

It’s been rumoured that Google uses the Lighthouse scores as a ranking factor. If true, it would mean that a website which performs well in Google Lighthouse would also perform well in Google search results. Even if this isn’t true, we know for a fact that Google wants to return results that are relevant and provide a good user experience. The last thing it wants is to guide people to websites that are poorly built, otherwise they’d start using different search engines. Therefore it’s not a giant leap to speculate that Google at least judge websites using the same set of criteria.

Even if search discoverability isn’t important to your organisation, Lighthouse is a mature and evolving tool to help you benchmark the build quality of your website.

So what does a Google Lighthouse audit look for?


Website performance is all about how quickly your website loads for the end user. In other words, page speed. Factors that can affect this are the way in which the code is written, the server that it resides on and the overall page weight.

Why website performance matters

As mentioned above, it’s in Google’s interest to link to a website that performs well and we do specifically know that page speed is a ranking factor. But, just as important, is giving people who use your website the best possible experience. No one enjoys browsing a slow site and even small delays can have a negative impact on business goals:

The BBC reported that they lost an additional 10% of users for every additional second their website took to load.

It’s also important to understand that incremental improvements, when scaled up, can result in large increases in revenue:

For Mobify, every 100ms decrease in load speed worked out to a 1.11% increase in session-based conversion. This led to an average annual revenue increase of $380,000. 

Google provide a handy calculator at the bottom of this page to help businesses understand what improving performance can mean on revenue.


Website accessibility is the practice of building websites in such a way that everyone can use it regardless of disability type or severity of impairment. There are many types of disabilities but as an example, people with visual impairments often use screen reading devices in order to read out the text that is on a web page.

Why website accessibility matters

It’s obvious that the more people who are able to use your website the better. But there are less obvious reasons why accessibility matters for websites:

  • In an age of social media it doesn’t take much for damage to be done to your reputation if someone complains.
  • In some countries, it’s a legal responsibility for all websites (and is a legal requirement for public sector websites in the UK). In 2018 alone over 2,000 website accessibility lawsuits were filed.
  • The chances are that if your website isn’t accessible to screen readers then it won’t be indexable by search engines either. In a way, Google is the biggest blind website user.

Search Engine Optimisation (SEO)

SEO is all about making your website appear high enough in the search engine results page when someone searches for a key phrase. There are many aspects that go into this, such as the content on your website and its domain authority, however, the Google Lighthouse SEO score is specifically auditing your code to see if it's constructed correctly for search engines to understand it. This is why it’s so interlinked with accessibility.

Why website SEO matters

This is probably an obvious one to many but the higher your website appears on a search engine page, the more visitors your website will have:

The research shows that 75% of people never scroll past the first page of search engines

This isn’t just important for B2C:

57% of B2B marketers stated that search engines generate more leads than any other marketing initiative, and 93% of all online experiences start with a search engine.

Progresive web app

Did you know that your website could give messages to people even when you’re not offline? That’s just one example of a what a web app could do. Websites can do many things that are more associated with native apps, you can even ask visitors to “install” it which adds an icon to their phone’s home page. IOS was a little late to the party on this but watch this space as communications teams become more aware of it

Why website Progressive Web Apps matter

If you don’t need your website to act like an App and it’s already built to be responsive so that it works seamlessly on mobile, then this isn’t as important. But if you’re considering paying the extra cost to build and maintain a separate App, then a PWA should be something to consider. It also means you’re not reliant on the whims of the App Store rules.

Before commissioning an app it’s important to consider if people will actually want to use it. 

25% of apps downloaded around the world are only ever used once

Best practice

In one sense, best practice encapsulates all of the above, because… well all of it is “best practice”! For Lighthouse, this one is all about “code health” and it encapsulates additional checks that don’t easily fit into the above. 

Why website Best Practice matters

Two of the most important checks here are for deprecated technologies and security.

Avoiding the use of deprecated technologies means your website will work more consistently across modern and future browsers. This may avoid costs associated with upgrading the website code in the future.

Security isn’t just important for websites that have forms or accept online payments. Google Chrome now warns users if they are visiting a page that is not protected via HTTPS. I’m sure you don’t need me to tell you how important trust is in the mind of website visitors.

The return on investment

As a strategic digital agency, we know that build quality is only part of what makes an effective website. Just as important is the content, messaging and visual design. But It’s the combination of all of this that creates a good user experience. You could carry out the best user research and produce the most beautiful and compelling website in the world – but all of this is pointless if no one can find the website to begin with or if it’s too slow for anyone to use.

Unfortunately, getting this right often increases the costs to produce a website - you do tend to get what you pay for. Pre-built theme templates associated with Wordpress are often the biggest culprit due to their ‘one size fits all’ nature. When commissioning a new website it’s important to understand this and ask the right questions.

Anyone can audit their website using Google Lighthouse

One of the great things about Google Lighthouse is that anyone can run it. So if you’d like to check the quality of your website, just enter the URL in this page. As a guide, your website should be looking to score 90 at the very least across all of the scores it gives. If you do have any questions about this please feel free to leave a comment below.

This article was posted in SEO