The process of production affects the quality of the products produced. Related to this, good quality control is needed to improve product quality. This quality control can be done by improving methods or production processes that reduce product quality. PT. QRS is one of the companies engaged in the manufacturing of zinc coated steel sheets. The problem in the company is to see if variation from the product can lead to additional cost or loss in the company. Based on these problems, it is necessary to calculate the losses due to variations in the dimensions of the product in which the company must pay to achieve the desired specifications. To find out the initial problem we can analyze with Taguchi’s Quality Loss Function. Based on calculations, it was found that the value of the process capability index for the long dimension obtained was Cp = 0,5556. From the calculation of the company’s loss data, it was obtained at Rp. 17.111.796/month.