There are 3 metrics to pay attention to when testing a website’s load time & performance:
First Contentful Paint (FCP) time: how long it takes for the first pixels to load
Largest Contentful Paint (LCP) time: how long it takes for the largest image & text to load on the site. This is the most common way of measuring how long it takes for a site to be fully loaded for a visitor.
Cumulative Layout Shift (CLS): this is a measure of how “stable” the website is when loading (i.e. do images load in and stay in place or do they shift up/down when loading in the website)
Together FCP, LCP, and CLS has a strong impact a website’s conversion rate, organic ranking, paid marketing performance, and overall customer experience.
Here are the results of the audit:
The Therabody site has an above averageFCP time on mobile and desktop devices.
The Therabody site has an above averageLCP time on mobile and desktop devices.
The Therabody site has an above averageCLS on desktop devices.
The Therabody site has an below averageCLS on mobile devices.
The recommended CLS on mobile devices is <0.1. The Therabody site has a CLS of 0.17 CLS on mobile devices.
, websites that meet the recommended CLS threshold of 0.1 see 24% less abandonment of page loads by users. And that’s a considerable number of potential customers!
The site’s CLS is high on mobile due to unexpected large layout shifts.
A large layout shift refers to a significant and unexpected movement of web page elements during loading, causing visual instability. This shift can negatively affect user experience, especially when users are trying to interact with the page while it's still loading. For example, a button may suddenly move after a user attempts to click it, leading to misclicks or confusion.
There are several optimizations that can be performed to improve large layout shifts/CLS:
Defining the size for images and videos
Reserving space for dynamic content
Optimizing website fonts
Preloading code and images
In addition to improving CLS, there are a handful of other technical issues that are slowing down the site’s load time.
For example, there is excess/unused Javascript code that is slowing down the website. This is a the most common occurrence in ecommerce sites hosted on Shopify. Every app installed, theme change, and third party script (i.e. Facebook Pixel, Google Analytics, etc.) injects code into the site. Even if the app/theme is removed, the code stays behind, accumulating over time.
I would recommend a optimizing the site to improve CLS and loading times.
For more information about the optimization work we do at Roadrunner, click on the section titles Next Steps.
Mobile Page Speed Audit
Results
First Contentful Paint: 1.4 seconds
Explanation: First Contentful Paint (FCP) measures how long it takes for content to start appearing on a website. This is typically an empty box or plain text. It’s the first pixels rendered in for the site.
Optimal time for ecommerce sites is < 1.8 seconds.
Largest Contentful Paint: 2.4 seconds
Explanation: Largest Contentful Paint (LCP) measures how long it takes for a website to display its biggest single content element. It's one of the most common ways to measure page load time.
Optimal time for ecommerce sites is < 2.5 seconds.
Cumulative Layout Shift: 0.17
Explanation: Cumulative Layout Shift is a measure of how “stable” your website it after it first renders. A website that has content shift down as more object load will have a higher score. Cumulative Layout Shift is one of the core ranking factors for Google.
Optime score for ecommerce sites is < 0.1.
Technical Issues
Reduce Javascript Execution Time
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that the browser has to process every time the site is loaded. There are four ways that Javascript code can accumulate on your site: when you connect a new Shopify app, when you use certain themes, when you use third-party scripts such as Facebook Pixel or Google Analytics, and if you have custom code on your site. The biggest culprit is Shopify apps. Each app “injects” a bit of code into your site. Even if the app is deleted, the code it injects stays behind. Over time, this code will slow down your site’s load time.
Minimize main-thread work
Main thread overload happens when too many tasks, like heavy JavaScript execution, complex CSS code, and third-party scripts, are processed simultaneously. This slows down the site’s load time. The best way to fix this is to delete unused Javascript, compress essential Javascript code, and remove unnecessary third party scripts.
Optimize Largest Contentful Paint (LCP)
The LCP takes up a considerable amount of main thread resources when loading. As a result, it needs to be optimized through image compression, preloading important page elements, and eliminating unused CSS and Javascript files.
Reduce the impact of third-party code
Third-party scripts, such as ads, analytics, and social media widgets, can slow down your site. Delaying the firing of analytics, or deferring them from using the main thread, can improve performance.
Desktop Page Speed Audit
Results
First Contentful Paint: 1.2 seconds
Explanation: First Contentful Paint (FCP) measures how long it takes for content to start appearing on a website. This is typically an empty box or plain text. It’s the first pixels rendered in for the site.
Optimal time for ecommerce sites is < 1.8 seconds.
Largest Contentful Paint: 2.4 seconds
Explanation: Largest Contentful Paint (LCP) measures how long it takes for a website to display its biggest single content element. It's one of the most common ways to measure page load time.
Optimal time for ecommerce sites is < 2.5 seconds.
Cumulative Layout Shift: 0.09
Explanation: Cumulative Layout Shift is a measure of how “stable” your website it after it first renders. A website that has content shift down as more object load will have a higher score. Cumulative Layout Shift is one of the core ranking factors for Google.
Optime score for ecommerce sites is < 0.1.
Technical Issues
Reduce Javascript Execution Time
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that the browser has to process every time the site is loaded. There are four ways that Javascript code can accumulate on your site: when you connect a new Shopify app, when you use certain themes, when you use third-party scripts such as Facebook Pixel or Google Analytics, and if you have custom code on your site. The biggest culprit is Shopify apps. Each app “injects” a bit of code into your site. Even if the app is deleted, the code it injects stays behind. Over time, this code will slow down your site’s load time.
Minimize main-thread work
Main thread overload happens when too many tasks, like heavy JavaScript execution, complex CSS code, and third-party scripts, are processed simultaneously. This slows down the site’s load time. The best way to fix this is to delete unused Javascript, compress essential Javascript code, and remove unnecessary third party scripts.
Optimize Largest Contentful Paint (LCP)
The LCP takes up a considerable amount of main thread resources when loading. As a result, it needs to be optimized through image compression, preloading important page elements, and eliminating unused CSS and Javascript files.
Reduce the impact of third-party code
Third-party scripts, such as ads, analytics, and social media widgets, can slow down your site. Delaying the firing of analytics, or deferring them from using the main thread, can improve performance.
It’s common for the same technical issues to affect the site on mobile and on the web. The issues have a greater effect on mobile devices due to the lower processing power.
Next Steps
Anyone selling products on the internet should think about their website’s speed. It plays a major part in how effectively a website can turn visitors into paying customers.
found that a 0.1 second improvement in website speed can increase overall conversion rates by 8.4%.
Other sources have found interesting links between fast site speed and better SEO, lower cost acquisition costs when using paid ads, and an increase in repeat purchases.
Let’s make it real with an example. Let’s say an ecommerce site get’s 100,000 visitors per month and has a 3% conversion rate.
If that site is optimized for speed, and see a 20% increase in conversion rates, it would go from 3000 sales/month to 3600 sales/month. At an AOV of $30, that’s an addition $20,000 per month in sales for every 100,000 visitors.