A time-error-compensating apparatus and method corrects errors in a real-time clock caused by temperature fluctuations or other external influences. The apparatus includes a frequency counting unit which counts a high-frequency clock signal and a low-frequency clock signal, and a time compensating unit which computes a clock count compensation value based on a comparison of the count values of of the low-frequency and high-frequency clock signals. Correcting time using a high-frequency clock is highly desirable because a clock of this type has proven to be accurate in high external stress conditions. Use of this clock also allows the real-time clock to be implemented as a low-frequency, inexpensive low-frequency clock. The method and apparatus are well suited to correcting time information in the terminals of a mobile communications system, or in any other system or device where time tracking is sought.