This work is focused on the development of an easy handling, quick, and reliable tool for the preliminary sizing of parachute systems. The tool also includes the capability to check the proposed design by performing a descent phase trajectory calculation. The preliminary design is based on the system requirement (vehicle mass and maximum acceleration induced by parachute), and mission requirement (descent system triggering condition and landing final conditions, vehicle aerodynamic drag). The outputs of the preliminary design include: • Number of stages and end conditions for each of them • Preliminary geometrical sizing for the identified parachute • Preliminary materials selection and mass budget definition for the selected parachutes A set of dedicated database related to type of parachutes (including scaling geometrical factors and deceleration characteristics)and material properties (strength and mass) have been integrated in the model.