Currently, determination of an entrance or exit hole/wound on a skull is largely based on the word description issued by a medical examiner or a forensic pathologist in an autopsy report. Such description is an approximate dimension with rulers (plastic or paper) placed next to the bullet holes, lacking specific quantitative measurements due to the small size of bullet holes and available devices. In this study, a novel technique, namely a digital viewer, is utilized to measure the common characteristics of the entrance/exit holes, providing a more objective description. Using a quasi-experimental design, a simulated skull with an entrance and an exit hole is used to perform the linear, triangular, and circular measurements, producing real time measurements and near 3D images of gunshot holes on a skull at an in situ position. As a result, a more objective and accurate image is obtained for a more scientific entrance-exit gunshot holes determination.