In this work, we provide a derivation of a simple approximation to estimate the largest charge a given molecule can hold until the fragmentation of this ion into smaller charged species becomes more energetically favorable. This approximation solely relies on the ionization potentials, electron affinities of the parent and fragment species, and the neutral parent's dissociation energy. This allows for a significant reduction of the computational time for estimating the polycationic stability. The same approximation for the maximal possible charge of the molecule can be further parametrized to produce an analytical approximation for the maximum charge, depending on various molecular properties, such as the size of the molecule. We demonstrate the applicability of our approach with two showcase examples, imitating the ISM-important species. The first case is chemically-bound π-conjugated hydrocarbons: linear polyenes and monocyclic annulenes that serve as simplified analogs of PAHs. The second case is helium clusters, illustrating the general applicability of the same approach to non-covalently bound clusters, such as PAH clusters and dust nanograins. 2 Thermodynamics of the polycation's dissociation Let us define the thermodynamic stability of the polycation through its dissociation reaction via the following formal chemical reaction: