These kinds of reports can be prepared through small quantitative research projects or desk researches and estimate the market size. There is a variety of market estimation methods. Some methods provide simple estimations. They don’t need much time and money. But some methods can estimate market size in regard of different customers' type with small errors. Through these methods market segmentation and calculation of each segment would be possible. Totally estimation and calculation of market size is one of the most important indexes for marketing manager's decision