Uniform complex-scaling is a widely used technique to calculate the energies and lifetimes of resonances (or metastable states). In this method the coordinates in a system’s Hamiltonian are rotated into the complex plane. This leaves the bound states untouched but reveals new stationary points in the spectrum corresponding to the resonances. With this NanoHUB tool, one-electron resonance energies and lifetimes can by calculated via a complex-scaled Schr“dinger equation solved with the Fourier Grid Hamiltonian method. The parameters of the potential can be modified to explore how the energetic position and width (inverse lifetime) of the lowest energy resonance (LER) are influenced by the potential’s shape. In addition, the complex density associated with the LER is caclculated. From this complex density one can learn about geometrical preferences of decay (a sort of 1D reactivity of the metastable state).