A method of inputting a character is provided. The method includes receiving a user input for inputting a character, obtaining a plurality of candidate characters corresponding to the user input, sequentially converting the plurality of candidate characters into a selectable character state whenever a predetermined character conversion cycle ends, updating a character conversion cycle based on an amount of time it takes to sequentially convert the plurality of candidate characters into the selectable character state, before a user input for selecting a selectable character is received, and sequentially converting the plurality of candidate characters into the selectable character state whenever the updated character conversion cycle ends.