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How do you improve your website's Lighthouse performance score?

by Becky Cable ON Nov 20, 2020

What is a Lighthouse performance score?

Good old Google released an SEO tool called Lighthouse back in 2018 that offers insight on how to improve the quality of your website pages.

This audit is an open-source automated tool that checks a page’s performance, accessibility, and more.

To the right here is our latest Lighthouse score, showing 100% across the board.

Across the board - we aim to achieve (and do) the highest possible score on Performance, Accessibility, Best Practices, and SEO.

So, with achieving this on our own website, you're well advised to place your trust in us to do the same for yours.

The scores that you see at the top of your Lighthouse report represent the page's score for that particular category. This guide explains how Lighthouse calculates those scores.

The scores that you see next to Performance, Accessibility, Best Practices, and SEO at the top of your Lighthouse report represent your score for that category.

What the Tool Checks

So what exactly are these reports that the Google Lighthouse audit provides? The audit reports on a few key factors for each web page, which are:

The report details how visitors interact with these different elements of the page - and what issues need fixing.


You already know that the speed with which a web page loads is of extreme importance for users. As the time it takes for your web page to load increases, so does the likelihood that your visitor will abandon their search. Your Lighthouse performance report helps with this.

The Lighthouse audit provides site performance reports under several categories including metrics, opportunities, and diagnostics. Metrics covers three main points of the loading process, showing you which page features are slowing things down.

The diagnostics of a page include reducing the length of chains required for page loading and deferring the downloading of unnecessary resources.


The Accessibility test contains the highest number of audits, at 35.

It's main goal is to rate how clear your website’s content is transmitted to visitors. These visitors include users of assistive technology; Google Lighthouse puts a high priority on delivering accessible content to all website users. To do well in the Accessibility audit, it is important for your website to have well-structured elements with discernible names that describe your content clearly.

Best Practices

We already know that Google has a lot of rules. This element ensures that web developers are following the rules and implementing best practices when it comes to web design. This feature also helps users avoid performance pitfalls and modernise the pages.

Search Engine Optimisation (SEO)

Audits nine search engine optimisation basics. The current list of audits was designed to validate and reflect the SEO basics that every site should get right, and provides detailed guidance to developers and SEO practitioners of all skill levels.

It gives your business get an idea of how it will perform in Google and other search engines.

Great. But how do I get the best Lighthouse performance score for my site?

Sit tight. We are about to tell you.

The short answer is:

Source a good quality, knowledgeable website developer to do it for you.

Seriously though, an experienced developer will look behind the scenes at the finer details of performance, accessibility, and best practice methods.

A very good way of checking a website developer's credentials is by running their own website through Lighthouse to check their score. After all, if they can't achieve perfect scores for themselves, how are they going to do it for you?

What about AMP websites?

We have found AMP-developed websites naturally score higher than non-AMP sites, as AMP reinforces best practice use. And Google likes AMP. Obviously.

You can learn more about the major benefits of AMP powered websites here.

Some simple things you can do in the meantime to aim for your own 100% Lighthouse performance score:

  • Cut down on the number of plug-ins and widgets
  • Improve the first meaningful “paint” (i.e. the amount of time it takes the user to see primary content)
  • Focus on your high impact pages
  • Improve text size and contrast to make content easier to read
  • Reduce unnecessary elements. If it doesn't serve a purpose, remove it

We recommend focusing on the most severe issues listed in your results. The issues listed in red within the report. By resolving the severe issues first, you will probably find most of the secondary issues (listed in an orange colour) will also be resolved. Make sure to re-run your report each time.

Our advice is to wash, rinse, and repeat.

Oh, and Life Lesson: Don’t use original images. Compress them down and your site will be all the better for it.

Hopefully you'll have picked up a couple of tips to help improve your Lighthouse score. If you're in the market for levelling up your existing site, download our free guide below, get in touch with us and we will get your website well on the way to those perfect Lighthouse scores.