Conversion rate and load speed

In this post I want to make an overview of available researches and case studies on the topic of CVR and load speed. I want you to be informed about potential benefits of investing in the load speed of your Shopify store.

There are lots of information on this topic on the internet, however I find that most of them are throwing numbers without pointing to the data source. I will only quote data which comes from confirmed respectable sources. Though many of good studies are quite old, I believe that the main points are still true, or even more critical.

Here are the excerpts of relevant info.

Portent internal research of 10 ecommerce websites and over 26000 landing pages - portent.com 1

These are our findings when comparing site speed versus conversion rates:

  • 0-4 second load time is best for conversion rates
  • The first 5 seconds of page load time have the highest impact on conversion rates
  • Website conversion rates drop by an average of 4.42% with each additional second of load time (between seconds 0-5)
  • Website conversion rates drop by an average of 2.11% with each additional second of load time (between seconds 0-9)
2015 State of the Union: Ecommerce Page Speed & Web Performance report - radware.com 2
  • A site that loads in 3 seconds experiences 22% fewer page views, a 50% higher bounce rate, and 22% fewer conversions than a site that loads in 1 second, while a site that loads in 5 seconds experiences 35% fewer page views, a 105% higher bounce rate, and 38% fewer conversions
  • 57% of consumers will abandon a page that takes longer than 3 seconds to load
  • A user who has to endure an 8-second download delay spends only 1% of their total viewing time looking at the featured space on a page. In contrast, a user who receives instantaneous page rendering spends 20% of their viewing time within the feature area of a page.
Why Web Performance Matters: Is Your Site Driving Customers Away? - www.gomez.co 3

According to studies by the Aberdeen Research Group, 1-second delay meant a 7% reduction in conversions.


In 2009, an ecommerce site and a media site participated in an innovative study that randomly divided their 14,000 visitors into two groups: one visited an optimized Website while the other visited a site that remained untouched. Performance optimization improved the conversion rate by 16.07% and the order value by 5.51%.


Shopzilla.com improved their load speed from 6 seconds to 1.2 seconds, which lead to 5-12% increase in revenue.

How to Improve Your Conversion Rates with a Faster Website - www.moz.com 4

Back in 2006, Amazon presented one of the first studies linking a clear causation between page load time and online customer revenue, summarized in Greg Linden's presentation Make Data Useful. Through A/B testing, Greg showed every 100 millisecond delay in page rendering time resulted in a 1% loss of sales for Amazon.


In more recent research, Intuit presented findings at Velocity 2013 from their recent effort to reduce page load time from 15 seconds to 2 seconds. During that effort, they observed a dramatic increase in conversions for every second shaved off their page load time, in a stair step that decreased with increasing speed. Specifically:

  • +3% conversions for every second reduced from 15 seconds to 7 seconds
  • +2% conversions for every second reduced from seconds 7 to 5
  • +1% conversions for every second reduced from seconds 4 to 2.

In another recent report, Kyle Rush from the 2011 Obama for America campaign site showed through A/B testing that a 3-second page time reduction (from 5 seconds to 2 seconds) improved onsite donations by 14%, resulting in an increase of over $34 million in election contributions.


In fact, there's a wide body of research supporting clear economic benefits of improving your site performance, and clearly the slower your site is, the more you have to gain. Additionally, the higher your traffic, the larger the impact each millisecond will yield.

Firefox browser downloads and Page Loading speed - blog.mozilla.org 5

After implementing these changes in an A/B test, we saw impressive results. Previously, we predicted a 1 second reduction in page load speed would improve download conversions by 2.7%. In reality, our optimized experimental variation shaved 2.2 seconds off the average page load time and increased download conversions by 15.4%!


With 275,000 daily visitors, a 15% improvement on this single English page translates to 10.28 million additional downloads per year. And, if we’re able to achieve a similar performance boost across our other top landing pages, we’ll drive in excess of 60 million yearly Firefox downloads.

The 2019 Page Speed Report Stats & Trends for Marketers - unbounce.com 6

Over October/November 2018, Unbounce surveyed 750 consumers and 395 marketers, and—while both groups already know slow page load times affect consumer behavior—nobody’s doing enough to avoid the consequences. Key Findings:

  • When it comes to waiting for pages to load, most consumers think they’re more patient than they actually are
  • Nearly 70% of consumers admit that page speed impacts their willingness to buy from an online retailer
  • Although they know it’s important, the majority of marketers aren’t making page speed a priority

At 2018's Call to Action Conference (CTAConf) in Vancouver, we chatted with 188 attendees to look at the performance of their landing pages. Based on this check-in, 85% of participants' landing pages were slower than Google’s recommendation of 5 seconds or less at a 3G connection.

Credits and links for further reading:

1 - Site Speed is (Still) Impacting Your Conversion Rate - portent.com
2 - 2015 State of the Union: Ecommerce Page Speed & Web Performance report - radware.com
3 - Why Web Performance Matters: Is Your Site Driving Customers Away? - www.gomez.com
4 - How to Improve Your Conversion Rates with a Faster Website - www.moz.com
5 - Firefox browser downloads and Page Loading speed - blog.mozilla.org
6 - The 2019 Page Speed Report Stats & Trends for Marketers - unbounce.com

The sooner you take action towards improving your load speed, the faster you'll be able to take advantage over your competition. Send an email to receive a Complementary Store Diagnostic (more info below).