Google Lighthouse Performance

The Google Lighthouse performance score is a metric that measures the speed and performance of a website. It’s an overall score that ranges from 0 to 100 and is generated based on a number of different performance metrics, such as the time it takes for a website to load, the time it takes for a website to become interactive, the size of the resources used by the website, and other factors that impact the user experience.

A high performance score in Google Lighthouse indicates that a website is fast and responsive, which can lead to a better user experience and improved search engine rankings. On the other hand, a low performance score can indicate that a website is slow and unresponsive, and can negatively impact the user experience.

Mobile Performance
Desktop Performance

Core Web Vitals

Core Web Vitals are a set of specific factors that Google considers important in a webpage’s overall user experience. Core Web Vitals are made up of three specific page speed and user interaction measurements: Largest Contentful PaintFirst Input Delay, and Cumulative Layout Shift.

Largest Contentful Paint6.0 s1.5 s< 2.5 s
First Input Delay250 ms170 ms< 100ms
Cumulative Layout Shift0.1040.012 0.1

Tracking scripts

All the tracking scripts on the site generated ~218 KB of data

A tracking script is a code snippet designed to track the flow of visitors who visit a website. Media, advertising, and analytics organisations will provide a script to add to your website that sends data directly to their servers. This data can then be used to measure goals and conversions, analyse user behaviour, and influence advertising campaigns.

Consider how much of this data you actually need and use? How often do you review the analytics data, and does this inform genuine change? Are you actively running social media campaigns? Consider pausing or removing tracking scripts that aren’t being actively used. 5 86 KB 4 114 KB 2 751 B 12 5 KB 4 8 KB 1 272 B 2 2 KB 1 863 B 1 787 B 1 756 B 1 787 B


Subset large font files

Fonts should be subsetted to reduce the file size, improve performance, and reduce emissions. Subsetting a font involves removing any characters that are not needed for a particular use case, resulting in a smaller file size and faster page load times. Some specific reasons why fonts should be subsetted include:

  1. Reduced file size: Subsetting a font removes any unused characters, which can result in a smaller file size. This can help to reduce the amount of data that needs to be downloaded, leading to faster page load times and lower emissions.
  2. Improved performance: Fonts that are subsetted are faster to load and render than fonts that are not subsetted. This can help to improve the overall performance of a website, leading to a better user experience.

Overall, subsetting fonts is a good practice for anyone looking to optimize the performance and reduce the emissions of a website of a website.

325e6ad0-38fb-4bad-861c-d965eab101d5-3.woff ~69 KB ~51 KB
dls-icons.woff ~56 KB ~38 KB
3be50273-0b2e-4aef-ae68-882eacd611f9-3.woff ~37 KB ~19 KB

Convert font files to woff2

WOFF2 is considered to be the best font format for web use because it provides a good balance of file size and compatibility. Some specific reasons why WOFF2 is a good font format include:

  1. Small file size: WOFF2 is a compressed font format, which means that it has a smaller file size compared to other font formats like TTF or OTF. This is important for web use because smaller file sizes can help to reduce the amount of data that needs to be downloaded, leading to faster page load times.
  2. High-quality font rendering: WOFF2 provides high-quality font rendering, making it a good choice for use on the web.

It’s worth noting that WOFF2 is not the only font format that can be used on the web, and there may be cases where other formats like WOFF or TTF are more suitable, depending on the specific requirements of the website. However, for most cases, WOFF2 is considered to be the best font format for web use due to its combination of small file size, good browser support, and high-quality font rendering.


Remove third party font files

Font files should be loaded from the same hosting as the website because

  1. Increased loading time: Third-party sub-resources, such as scripts, fonts, or images, need to be downloaded from a separate server before they can be displayed on the website. This can increase the overall loading time of the page, leading to a slower user experience.
  2. Dependence on external servers: The loading of third-party subresources is dependent on the availability and performance of the external servers that host them. If these servers are slow or unavailable, it can result in slow page loading times or even errors.
  3. Increased risk of security threats: Third-party subresources can introduce security risks to a website, as they can contain malicious code or be used to track user activity.

First Contentful Paint

First Contentful Paint (FCP) is a performance metric that measures the time it takes for the first piece of content to be rendered on the screen when a user navigates to a web page. This content can be any visual element on the page, such as text, images, or a background color.

FCP is important because it directly affects the perceived speed of a website, and can impact user engagement and conversion rates. A faster FCP can lead to a better user experience and improved performance.

Here are a few ways you can optimise your FCP:

  1. Optimise images: Large, unoptimised images can slow down a page’s FCP. You can optimise images by compressing them, reducing their dimensions, and choosing the right format for each image.
  2. Minimise HTTP requests: Each resource requested by a web page, such as images, scripts, and stylesheets, requires a separate HTTP request. Minimising the number of HTTP requests can help to reduce the time it takes for a page to render.
  3. Prioritize critical content: Prioritizing critical content, such as above-the-fold content, can help to ensure that users see something on the screen quickly, even if the rest of the page is still loading.
  4. Reduce server response time: A slow server response time can significantly impact FCP. Optimizing server-side code and server settings can help to reduce response times and improve FCP.
  5. Use a performance monitoring tool: There are many tools available that can help you monitor your website’s performance, including FCP. These tools can help you identify performance issues and track your progress as you implement optimizations.
Timing2.2 s0.6 s

Largest Contentful Paint

Timing6.0 s1.5 s

Total Blocking Time

Timing1,030 ms160 ms

Cumulative Layout Shift


Speed Index

Timing8.7 s2.8 s

Time to Interactive

Timing10.9 s3.3 s

Max Potential First Input Delay

Timing250 ms170 ms

First Meaningful Paint

Timing2.2 s0.6 s

Eliminate render-blocking resources

InsightPotential savings of 1,010 msPotential savings of 280 ms

Properly size images

InsightPotential savings of 40 KiBPotential savings of 149 KiB

Defer offscreen images

InsightPotential savings of 55 KiB

Minify JavaScript

InsightPotential savings of 4 KiBPotential savings of 4 KiB

Reduce unused CSS

InsightPotential savings of 54 KiBPotential savings of 41 KiB

Reduce unused JavaScript

InsightPotential savings of 226 KiBPotential savings of 222 KiB

Reduce initial server response time

InsightRoot document took 1,310 msRoot document took 2,250 ms

Serve static assets with an efficient cache policy

Insight11 resources found11 resources found

Avoid an excessive DOM size

Insight1,521 elements1,523 elements

Reduce JavaScript execution time

Timing3.3 s1.3 s

Minimize main-thread work

Timing5.3 s2.3 s

Minimize third-party usage

InsightThird-party code blocked the main thread for 640 msThird-party code blocked the main thread for 150 ms

Image elements do not have explicit width and height