This study develops a mathematical model for room allocation in a small-scale accommodation business by simultaneously considerin

g daily and monthly stays under capacity constraints. The model incorporates time-varying demand, fixed and variable costs, and opportunity costs arising from inefficient resource utilization. Framed within revenue management and operations research, the proposed approach is formulated as a pure integer linear programming model and solved using LINGO. The empirical analysis is based on real operational data from an accommodation facility consisting of 35 rooms classified into six room types, offering both short-term and long-term stays. Historical demand data over a one-year period are integrated into the model. The results demonstrate that the proposed model achieves a global optimal solution and significantly improves total profit compared to the existing allocation policy. Furthermore, the findings emphasize the importance of opportunity cost in room allocation decisions and show that a time-dependent mixed allocation strategy between daily and monthly stays enhances capacity utilization while systematically reducing revenue loss from unsold rooms.