According to Mental accounting theory, humans sort money according to their psychological purpose. It
plays a major role as a means of self-control. However, humans sometimes make mistakes that violate very
simple economic principles. Many consumers experience this mistakes. So consumers use account book to
manage their income and expenses. These days, they use mobile account book applications. And because of
platform characteristics, there are various user interfaces. This paper examines an efficient user interface
design that can reduce errors caused by mental accounting and support rational economic activities. For
this, we compared and analyzed households exposed on top of Application store based on advanced
research on Mental Accounting. Through this case study, We found some cases of efficient user interface
for reasonable consumption. In further studies, We will design optimal account book’s UI and do a usability test based on this.