A display device includes a display panel having a display region and a panel driver that drives the display panel based on input image data. The panel driver calculates a normal driving frequency for driving a first partial region and a low frequency for driving a second partial region when the input image data represents a moving image for the first partial region and represents a still image for the second partial region, calculates a consumption power required to drive the display panel when an entire section of the second partial region is driven at a same low frequency, calculates a consumption power required to drive the display panel when a partial section of the second partial region and a remaining section of the second partial region are driven at mutually different frequencies, and determines a driving frequency of the second partial region by comparing the consumption powers.