A data compensation device includes a current calculator which calculates an average current of each of blocks included in a pixel array based on an input data, a data enable signal, a horizontal synchronization signal and a vertical synchronization signal, a voltage drop info provider which provides a bus voltage drop information of predetermined bus points and an array voltage drop information of predetermined array points, the bus points being included in a power supply bus wiring which is connected to the pixel array, the array points being included in the pixel array, a data compensation circuit configured to provide a compensation data corresponding to the input data based on the average current, the bus voltage drop information and the array voltage drop information, and an adder configured to provide a compensation result data by adding the input data and the compensation data.