A display device includes a pixel column including first to n-th pixels connected to a same data line and different gate lines from each other, a data driving chip which outputs a test data voltage in a test mode and outputs image data voltages in a normal mode, a sensing circuit which is electrically connected to the data line and the data driving chip in the test mode, senses a current output to the first pixel during a first period, and senses a current output to an i-th pixel during a second period, and a signal controller which compares a reference charge amount calculated based on the current sensed during the first period to a first charge amount calculated based on the current sensed during the second period and compensates for a level of an image data voltage applied to the i-th pixel among the image data voltages based on the compared result.