A system-on-chip includes: a dynamic power monitor configured to generate a power detection signal by calculating an amount of power consumed by a functional circuit in real time; a frequency controller configured to detect an idle period and a running period of the functional circuit in response to the power detection signal, and generate a clock control signal based on the power detection signal; and a clock controller configured to change a frequency of a clock signal provided to the functional circuit, based on the clock control signal. The running period includes: a first running period in which the frequency of the clock signal has a first value based on the clock control signal; and a second running period in which the frequency of the clock signal has a second value that is greater than the first value based on the clock control signal.