Effects of the Font Size and Line Spacing of Simplified Chinese Characters on Smartphone Readability

In this study, we explored the effects that the font size and line spacing of simplified Chinese characters had on their readability on smartphones. One hundred and fifteen participants were recruited to complete Chinese text comprehension tasks and provide user preferences on a 5.9-inch smartphone. Nine test conditions were studied, consisting of three font sizes (10-, 12- and 14-point) and three line spacing variations (1.25-F, 1.5-F and 2-F). The results showed that both font size and line spacing significantly affect reading time, but only font size significantly affects reading accuracy; font size, line spacing and the interaction between them have significant effects on the difficulty of reading and the degree of visual fatigue. Medium and large font sizes are more comfortable to read with large line spacing, while small and medium font sizes are more attractive with large line spacing. The results provide useful information for mobile text interface design.