Effects of Smartphone Sizes and Hand Use Types on Usability

This study examined the effects of smartphone sizes and hand use types on usability using actual smartphones. Three smartphone sizes (small, regular, and large) and two hand use types (one-handed and two-handed) were assessed across eight usability measures, including error count, completion time, mental workload, physical discomfort, accuracy, convenience, rapidity, and preference. Thirty participants performed tasks using different smartphone sizes. The results showed that the regular-sized smartphone with two-handed use type had the highest usability, whereas the large-sized smartphone with one-handed use type had the lowest. The small-sized smartphone resulted in more errors when used with two hands, suggesting that screen size affects input accuracy depending on the hand use type. Overall, smartphone usability is influenced by both screen sizes and hand use types. These findings provide valuable insights into how these factors impact usability and offer practical guidelines for designing smartphones that better meet user needs.