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 Paint15.0 s3.3 s< 2.5 s
First Input Delay130 ms20 ms< 100ms
Cumulative Layout Shift0.30.281 0.1


Optimise images

By optimising the following images, roughly 2 MB could be removed from the transfer size, about 56%. This would reduce the CO2 generated per page load from 0.77g grams to 0.34 grams.

Images should be optimised for the web for several reasons:

  1. Reduced file size: Optimizing images can result in a smaller file size, which can help to reduce the amount of data that needs to be downloaded. This can lead to faster page load times and improved performance.
  2. Improved user experience: Optimising images can help to improve the overall user experience, as pages with optimised images load faster and are more responsive.
  3. Lower emissions: Optimising images can help to reduce the emissions associated with data transfer, as less data needs to be transmitted over the network.
  4. Better accessibility: Optimising images can make them more accessible to users with slower connections or limited data plans.
Say_Their_Name_-_Bereaved_parents_-_Stillbirth.png 1 MB 46% 1 MB

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.

Platform-Bold-Web.woff2 ~28 KB ~10 KB
Platform-Regular-Web.woff2 ~26 KB ~9 KB

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

Timing15.0 s3.3 s

Total Blocking Time

Timing180 ms0 ms

Cumulative Layout Shift


Speed Index

Timing10.4 s3.7 s

Time to Interactive

Timing6.8 s0.7 s

Max Potential First Input Delay

Timing130 ms20 ms

First Meaningful Paint

Timing2.6 s0.7 s

Eliminate render-blocking resources

InsightPotential savings of 720 msPotential savings of 240 ms

Properly size images

InsightPotential savings of 382 KiB

Reduce unused JavaScript

InsightPotential savings of 260 KiBPotential savings of 258 KiB

Efficiently encode images

InsightPotential savings of 252 KiBPotential savings of 5 KiB

Serve images in next-gen formats

InsightPotential savings of 2,543 KiBPotential savings of 1,801 KiB

Enable text compression

InsightPotential savings of 69 KiBPotential savings of 69 KiB

Reduce initial server response time

InsightRoot document took 2,350 msRoot document took 2,270 ms

Avoid enormous network payloads

InsightTotal size was 3,821 KiBTotal size was 2,981 KiB

Serve static assets with an efficient cache policy

Insight23 resources found24 resources found

Avoids an excessive DOM size

Insight737 elements737 elements

JavaScript execution time

Timing0.9 s0.1 s

Minimizes main-thread work

Timing2.1 s0.4 s

Ensure text remains visible during webfont load


Does not use passive listeners to improve scrolling performance


Image elements do not have explicit width and height