Using specific capacity data is a suitable method for estimating aquifer transmissivity. Usually the specific capacity data are more easily available compared with time-drawdown data, therefore, by using specific capacity data can increase the number of transmissivity estimates in an aquifer. Numerous researchers have tried to obtain the relationship between specific capacity and transmissivity and many methods have been proposed which among them, the analytical approach based on the Theis formula is the most commonly used method. In this research, a simple approach using the Microsoft Excel software is proposed which is based on iteration algorithm, providing fast estimates of hydrodynamic coefficients in more points. This approach has been used in two different locations of Qom aquifer successfully, which in both of two considered places, the calculated hydrodynamic coefficients from the proposed approach are logically consistent with ones obtained from curve matching methods.