The results acquired by using the “New Method to Compute the Determinant of a 4x4 Matrix” are entirely equal with the results acquired by the other known methods until now. In base of this, we can conclude that this new method to compute the determinants of forth order is true and can be used only for the forth order determinant. The results achieved with this method are based on the Sarru’s rule used for computing the third order determinants. Using some combinations it is achieved that this method is applicable for the forth order determinants.