A digital to analog converter (DAC) converting a digital code to an output voltage and capable of self calibration. The DAC includes a self-calibration signal generator generating a self-calibration signal based on the output voltage, a constant current generator, a first and a second current provider and a current-voltage converter. The current generating elements of the first and second current providers provide proportional currents, and are enabled/disabled according to the self-calibration signal and the digital code, respectively. The constant current is divided into the actual working current generating elements of the first current provider, and an output current is generated by the actual working current generating elements of the second current provider. The output current is converted to the output voltage by the current-voltage converter.