Faster Sites, More Sales: Connecting Website Performance to Ecommerce Revenue

A faster site delivers a better a user experience, more engagement, and more revenue for your business.

Taryn Hardes
Technology Contributor
August 18, 2021

Slow websites are a waste of time and attention.

At SpeedSense, we’re on a mission to reclaim the world’s wasted time and focus. A faster site delivers a better a user experience, more engagement, and more revenue for your business.

“But how much of an impact will site speed really have on our revenues?”

Since the impact of site speed on ecommerce revenue varies wildly across brands and industries, it can often be very helpful to do a pilot project as a means to measure the impact and calculate ROI, helping forecast whether continued investment in site speed is worthwhile.

A case study: Website performance vs. ecommerce revenue

Let’s look at an example. This client came to us two years after a major re-platforming of their site. During the re-platform, as with most major migration projects, the scope was tightly constrained; the performance target was “no slower than the existing site”.

However, after launching their new website, performance soon became an issue—not only page load time but also site capacity—and had to be revisited. They wanted to run a test. If it could be proven that there was a positive return on the investment of site performance improvements, then it would be much easier to justify continued investment in site speed.

Site performance is nebulous—this client, like most, had no idea where to start. They weren’t sure which metrics to track, which tools to trust, or even how fast was “fast enough”. SpeedSense partnered to guide the team through this phase of uncertainty, and together we set out to prove their hypothesis: that a faster site would sell more.

How to measure site speed improvements

In the beginning of the project, we needed a method to measure the impact of web performance on ecommerce conversion and to ensure the improvement could be clearly attributed to the web performance improvements.

To do so, we needed a baseline map of how performance and sales conversion correlated. A “Before” snapshot.

A website—or even an individual page, for that matter—doesn’t have a single “speed”. Users are visiting on a variety of devices, across massive geographical regions, and a range of network types. This breadth of user experience is best captured as a distribution rather than a single data point like an average.

To begin, we extracted an initial snapshot of the distribution of page speed for every visitor and, overlaid onto that, the ratio of whether or not those sessions resulted in a sale.

Sessions and Conversion Rate by Average First Contentful Paint

Once graphed, the data allowed us to identify a correlation between site speed and sale likelihood. Within the current performance capabilities, conversion was indeed more likely for faster sessions.

The question was: would increasing site performance also increase the likelihood of sales?  Would abandonment decrease with faster sessions?

By making the site faster, we would change the shape of the traffic distribution, by pulling more of the sessions under the higher-converting slope of the graph. Now that we had a method for tracking our progress, it was time to speed up the site.

SpeedSense has a proven process for increasing the speed of our clients’ digital properties; we implemented it here for this client and can do the same for your business.

Result: Improved user experience

The most obvious, and most important impact of the improved site performance was an improved user experience. A faster site is more functional, and users are more willing and more likely to explore the site. Frustration is reduced, and the perception of the brand improves.

In this instance, we saw increased engagement metrics across the board and decreased abandonment as well. Mobile pages per session increased by almost 15%.

Result: Increased site conversion and ecommerce transactions

When we established our measurement method in the beginning of the project, our hope was that when we increased site speed (shifting the speed distribution to the left) we would see the likelihood of conversion increase in response. This hypothesis was indeed correct, and with the new site speed data, we saw the conversion rate increase.

Sessions and Conversion Rate by Average First Contentful Paint | Before & After | All Traffic

The effect on the average user experience, and therefore conversion rate, was even more pronounced for users on mobile devices.

Users not only visited more pages in their sessions, they were also more likely to convert. On mobile in particular, transactions increased by nearly 30% and sales per session increased by 16%.

Sessions and Conversion Rate by Average First Contentful Paint | Before & After | Mobile Traffic

Result: Increased revenue

So, how did the increased speed, engagement, and conversion rate impact the business’s bottom line? In this instance we saw an overall 7.6% increase in sitewide conversion. This figure translated to roughly ~$6 million in annual revenue lift for the client.

How improved site speed can work for you

This outcome could happen for your business, too. Your site speed is impacting your bottom line—and often it’s the last priority on website maintenance. It is hard to define, and the target is unknown, so better-defined priorities often compete for developer bandwidth.

A slow site costs your brand more than just lost sales—it also costs your business market share.

Stop letting ecommerce behemoths “steal your lunch money” as we like to joke.

Stop losing revenue to your competitors because their web performance is stronger. Contact SpeedSense today.


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