This paper presents a new method for determining the minimum zone for flatness of a point set obtained from a coordinate measuring machine. The two parallel planes that enclose the entire point set with minimum separation form the minimum zone for flatness. In this method, parallel planes are formed through each point in the point set for a range of plane orientations. Simplex search is used to determine the orientation of parallel planes that form the minimum zone. This method is applied to six example point sets and results are compared with other methods.