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.
FCP and LCP time are the most common metrics used when measuring website loading speed and performance. Together, these 2 have a strong impact on conversion rate, organic ranking, paid marketing performance, and overall customer experience.
Here are the results of the audit for 177 Milk Street online store (broken down by platform):
Mobile
Good FCP time
Poor LCP time
Desktop
Poor FCP time
Poor LCP time
FCP time
The recommended FCP time for an ecommerce website is <1.8s seconds.
177 Milk Street has an FCP time of 1.8 seconds on mobile and 1.9 seconds on desktop.
LCP time
The recommended LCP time for an ecommerce website is <2.5 seconds.
177 Milk Street has an LCP time of 3.2 seconds on mobile and 3.4 seconds on desktop.
This means that the 177 Milk Street online store is taking longer to load than what is recommended for ecommerce websites.
Research shows that longer loading times is linked to decreases in conversion rates, worse search ranking, worse paid marketing performance, and worse overall customer experience.
This extra load time might seem minimal; however, ecommerce is a game of milliseconds.
Research shows that every additional second you can shave off your website’s load time will lead to an increase in conversion rates. For example:
1 second improvement in page load time will increase mobile CVR by up to 27% (
This is why major ecommerce brands will spend tens-to-hundreds of thousands of dollars on their website’s performance.
Based on the site speed audit results, there are a handful of technical issues slowing down the website.
Most notably, the site is being slowed down by to excess Javascript, HTML, and CSS code present in the site. 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.
The best way to improve the website’s load time is with a codebase optimization.
During this process, necessary Javascript and CSS code is compressed to run more efficiently. Unused Javascript and CSS code is deleted altogether.
Based on the audit results, there are additional optimizations that can be performed that would improve the website’s load time. This includes, but isn’t limited to, text/image compression, preloading fonts and “heavy” on-page elements, enabling lazy loading, and more.
to help ecommerce companies maximize their conversion rate through proper site speed optimization. To date, we’ve helped more than a dozen Shopify sites increase their CVR by 20-50% through site speed optimization.
If you’d like to learn more about our site speed optimization services:
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: 3.2 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: 0.03
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.
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that is slowing down the site. 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: 1.9 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: 3.4 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: 0.19
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.
In short, this means that there is a substantial amount Javascript, HTML, and CSS code that is slowing down the site. 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.
Ecommerce Site Speed Statistics
Anyone selling products on the internet should think about their website’s speed. It’s the biggest lever any ecommerce business can make to increase sales and revenue.
And the research backs it up:
Improving a website’s load time by 1 second can increase mobile conversion rate by up to 27% (
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.