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 Paint2.1 s0.5 s< 2.5 s
First Input Delay130 ms70 ms< 100ms
Cumulative Layout Shift0.1050.049 0.1

Tracking scripts

All the tracking scripts on the site generated ~184 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 2 KB 2 161 KB 3 21 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.

BrownInlineLLWebPan-Regular-v1.1.woff2 ~33 KB ~16 KB
BrownLLWebPan-Regular-v1.1.woff2 ~26 KB ~8 KB
BrownLLWebPan-Bold-v1.1.woff2 ~26 KB ~8 KB

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.
Timing1.4 s0.4 s

Largest Contentful Paint

Timing2.1 s0.5 s

Total Blocking Time

Timing290 ms40 ms

Cumulative Layout Shift


Speed Index

Timing6.3 s2.7 s

Time to Interactive

Timing6.0 s1.5 s

Max Potential First Input Delay

Timing130 ms70 ms

First Meaningful Paint

Timing1.4 s0.4 s

Eliminate render-blocking resources

InsightPotential savings of 150 ms

Defer offscreen images

InsightPotential savings of 6 KiBPotential savings of 6 KiB

Reduce unused CSS

InsightPotential savings of 36 KiBPotential savings of 32 KiB

Reduce unused JavaScript

InsightPotential savings of 110 KiBPotential savings of 109 KiB

Uses efficient cache policy on static assets

Insight4 resources found4 resources found

Avoid an excessive DOM size

Insight1,104 elements1,199 elements

Reduce JavaScript execution time

Timing3.2 s1.4 s

Minimize main-thread work

Timing6.7 s3.0 s

Uses passive listeners to improve scrolling performance