In fact, the combined test data documents that the average site can increase its conversion rate by 35.26% solely through better checkout design.
And these figures are based on the testing of checkout processes from leading e-commerce sites, such as Walmart, Amazon, Wayfair, Crate & Barrel, ASOS, etc.

In this report, we have distilled all 2,700+ usability issues encountered by the test subjects into 134 checkout user experience guidelines, and prioritized them by UX impact – providing you with concise design guidelines that will help you improve the performance of your checkout process.