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 Paint20.5 s3.1 s< 2.5 s
First Input Delay220 ms60 ms< 100ms
Cumulative Layout Shift0.1450.148 0.1

Tracking scripts

All the tracking scripts on the site generated ~289 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. 2 130 KB 2 138 KB 3 21 KB 2 656 B


Optimise images

By optimising the following images, roughly 3 MB could be removed from the transfer size, about 61%. This would reduce the CO2 generated per page load from 1.41g grams to 0.55 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.
334158401_159671156884928_4988003960434553951_n.jpg 599 KB 11% 296 KB
334158401_159671156884928_4988003960434553951_n.jpg 599 KB 11% 296 KB
Telehealth-banner-1500x500_1360_333_c1.jpg 393 KB 7% 358 KB
331123284_1249470375950622_3026857773777305123_n.jpg 325 KB 6% 166 KB
Tony_Walton_valve_580_400_c1.png 309 KB 6% 283 KB
332589946_595244078729560_3463833698050272522_n.jpg 304 KB 6% 157 KB
331139401_991545308494210_3180151045277250351_n.jpg 278 KB 5% 75 KB
332294985_501101525552295_1950603170610615723_n.jpg 256 KB 5% 139 KB
HF_HumanFactors_2023_Shortcourse_580_400_c1.png 246 KB 4% 211 KB
333305108_936979177491328_3510161139187216476_n.jpg 222 KB 4% 51 KB
336008421_756211339238804_3840538700555730027_n.jpg 214 KB 4% 61 KB
ALS-Course_580_400_c1.jpg 199 KB 4% 174 KB
Monkeypox_580_400_c1.jpg 178 KB 3% 165 KB
Heatwave_2023_WEB_banner-v1.png 172 KB 3% 156 KB
AlfredHealth-staff-website-hero-banner-1300x313-300ppi-graphic.png 117 KB 2% 98 KB
334591940_603249661271954_6498365443223756430_n.jpg 107 KB 2% 34 KB
mental-health-category_270_180.jpg 84 KB 2% 73 KB
rehabilitation-category_270_180.jpg 79 KB 1% 69 KB
community-services-category_270_180.jpg 77 KB 1% 68 KB
aged-care-category_270_180.jpg 75 KB 1% 66 KB
Lizzy_in_park_yoga_low_res_v2_270_175.png 74 KB 1% 67 KB
medical-surgical-category_270_180.jpg 65 KB 1% 57 KB
emergency-intensive-care-category_270_180.jpg 61 KB 1% 53 KB
specialised-support-category_270_180.jpg 55 KB 1% 48 KB
diagnosis-investigation-category_270_180.jpg 53 KB 1% 47 KB
health-professionals.jpg 39 KB 1% 24 KB
patients-families-friends.jpg 38 KB 1% 22 KB
interpreter_logo.jpg 21 KB 0% 20 KB
auslan_logo.jpg 12 KB 0% 11 KB

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.

Metropolis-Medium.otf ~24 KB ~6 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.
Timing3.6 s1.0 s

Largest Contentful Paint

Timing20.5 s3.1 s

Total Blocking Time

Timing660 ms0 ms

Cumulative Layout Shift


Speed Index

Timing11.8 s3.3 s

Time to Interactive

Timing15.9 s2.3 s

Max Potential First Input Delay

Timing220 ms60 ms

First Meaningful Paint

Timing3.6 s1.0 s

Eliminate render-blocking resources

InsightPotential savings of 370 msPotential savings of 30 ms

Properly size images

InsightPotential savings of 2,212 KiBPotential savings of 2,930 KiB

Defer offscreen images

InsightPotential savings of 2,944 KiBPotential savings of 1,140 KiB

Reduce unused CSS

InsightPotential savings of 30 KiBPotential savings of 28 KiB

Reduce unused JavaScript

InsightPotential savings of 215 KiBPotential savings of 215 KiB

Efficiently encode images

InsightPotential savings of 1,050 KiBPotential savings of 1,050 KiB

Serve images in next-gen formats

InsightPotential savings of 3,048 KiBPotential savings of 3,048 KiB

Reduce initial server response time

InsightRoot document took 1,280 msRoot document took 1,050 ms

Avoid enormous network payloads

InsightTotal size was 5,484 KiBTotal size was 5,484 KiB

Serve static assets with an efficient cache policy

Insight47 resources found47 resources found

Avoids an excessive DOM size

Insight716 elements777 elements

JavaScript execution time

Timing2.6 s0.5 s

Minimizes main-thread work

Timing6.0 s1.4 s

Ensure text remains visible during webfont load


Minimize third-party usage

InsightThird-party code blocked the main thread for 1,330 msThird-party code blocked the main thread for 30 ms

Does not use passive listeners to improve scrolling performance


Image elements do not have explicit width and height