The paper analyzes various methods for determining forces during the opening of parachutes, based on the solution of a system of differential equations of motion of a mechanical system as a material point. The parachute inflation is a complex process in which the dynamics of air currents is closely related to the dynamics of the movement of the entire mechanical system: the payload, the parachute, and the involved air masses. The main problem in calculating the process of its inflation is that it is required to determine the maximum value of the loads during inflation, taking into account unknown parameters of the air mass mition directly near the parachute system and considering the implementation features of the design of parachutes. For the first time, a synthesized method for calculating loads when inflating parachutes is presented, considering the compliance of the structure, for which two methods were combined: (1) the existing one, to determine the reduced speed of the system when inflating the parachute, and (2) the new one, to determine the coefficient of parachute dynamism under conditions of “infinite” mass.