An apparatus and method for calculating and displaying local time for a plurality of cities in the world. The apparatus includes a memory for storing Greenwich mean time (GMT) information for each of the plurality of cities. The apparatus sets a reference time and counts the time that elapses from when the reference time is set. The apparatus calculates a local time of a city selected by a user, which is based on a difference between the GMT of the selected city and the GMT of a present location of the apparatus, the reference time and the counted elapsed time. The reference time may be either a time set by the user or a system time acquired from a signal generated from a remote system.