Auto-calibration of a touch screen

Methods and systems are provided for automatically calibrating a pointing device, such as a stylus, with a writing surface, such as a touch screen. In one example, an automated method is implemented to calibrate the writing surface based user inputs attempting to use the computer for functions other than calibration of the writing surface. The user inputs may be, for example, a user selecting a button within a non-calibration software application. The automated method may generate a miscalibration vector based upon where the user input was received and where the user input was expected. In yet another example, a bias field may be generated for the writing surface from the collected user inputs. In yet other examples, a computing device may comprise computer-executable instructions for performing one or methods of calibrating the writing surface.