Today, clothing factories have to strictly control their costs to survive and continue their success. Fabric cost constitutes about half of a garment cost. For this reason, it is important to calculate the fabric cost of a garment precisely. The study described in this paper aims to develop software that will calculate the fabric consumption of a garment in a clothing factory. It is not possible to study fabric consumption rapidly with garment models in existing computer-aided design systems, because these programs are not flexible enough to satisfy the needs of the customers. This study was planned to eliminate this imperfection. The part of the research involving shirts is examined in this paper. Shirt models were selected as the material, and input from a factory producing shirts was used. The software developed enables the fabric consumptions of different shirt models to be estimated in a speedy way. In addition, for repeat orders, it is possible to identify the most appropriate fabric width and marker plan by making use of marker plan information prepared previously.