Automatic estimation of the complexity of the parts from the products of CAD/CAM programs is very convenient for the estimation of manufacturing cost and time. The presence of holes significantly increases the complexity of the part; although, generally the holes will be opened with a secondary operation. If the holes are not removed, the manufacturing time and cost estimations of the neural networks will also increase without taking into consideration the secondary operation. In this paper, an algorithm is proposed to detect the round vertical holes and to estimate the complexity of the part without considering them. In this case, the cost and manufacturing time can be accurately estimated from the complexity of the part and the cost of the holes can be calculated and added to the total cost by using the information (number, location, size) provided by the algorithm.