Channel modeling is important for the design, evaluation, optimization and reliable wireless services. To characterize the channel, network planners should consider all sorts of losses during the propagation of the microwave signal in building materials. In this paper, the authors have developed a model for the total path loss calculation, which includes the effects of all the factors of penetration loss such as material loss, Free Space Loss (FSL), external wall loss, and losses due to antenna and building heights. The wall penetration losses are strongly material and frequency dependent. Moreover, the antenna height significantly affects wall penetration loss, especially at the lower positions of the building. It is believed that the presented model will help the planning engineers to plan a network that will provide uninterrupted services even inside a building.