Calculation of the moment capacity of reinforced concrete (RC) shear walls is a hard and time consuming task since they have more reinforcement rows. Although there exist some software to overcome this difficulty, those software require some expense. In this study, a simple equation is proposed to calculate the moment capacity (M-r) of rectangular RC shear walls which are designed according to the 2007-Turkish Earthquake Code. The proposed equation is simple because it includes variables which are easy to determine such as length and thickness of the shear wall, reinforcements in the boundary member at the tension zone and the axial load level. Moment capacities from the proposed equation are found to be very close to the ones from the detailed analysis. Using the proposed equation, charts for the moment capacity (M-r) of rectangular RC shear walls having varying dimensions and varying reinforcement ratio were developed and given in the appendix.