We investigate the mechanical stability (MS) of Formamidinium (FAXM₃) based perovskite structures using first-principles density functional theory calculations with Van der Waals interactions (DFT+vdW). The organic cation and its interaction with the inorganic species play a crucial role in determining the MS of the whole structure. We obtained an orthorhombic structure for all the calculations generated from the Pm3m space group. The elastic constant (EC) values considering all the nine independent deformations paths needed to define the MS. We noticed that both the cation and the hydrogen (H) to halogen (iodide, bromide, and chloride) charge distributions (CD) influence the EC results. The Mulliken-charge results clearly demonstrate the bonding interactions between the cation and the inorganic species.