Most seismic design methods generally use an equivalent-static lateral forces known as an elastic method to generate the lateral design force from the earthquake ground motions. Although this method is permissible under design ground acceleration, the accurate inelastic response is not well explained and still remains in extensive studies. In this regard, cumulative energy dissipation is an integral part of the design process in order to ensure that a seismic-resistant structure achieves the target structural performance. Existing studies have indicated the assessment method for the energy demand of a single degree of freedom system (SDOF) can be evaluated analytically, and the hysteretic energy can be described in relations with the system's input energy. Thus, this paper assesses the earthquake energy demand of SDOF systems using an analytical software so-called “Perform 3D”. This study also aims to discuss and compare the energy demand of SDOF systems from different analytical calculations with those from Perform 3D. The study considered a SDOF system represented by a lateral cantilever column with potential plastic hinge at its fix base. The SDOF systems was numerically performed under six earthquake ground motions selected from Pacific Earthquake Engineering Research (PEER) database. All the ground motions were intensively scaled to match the two design earthquake levels, namely design basis earthquake (DBE) and maximum considered earthquake (MCE). Nonlinear time history analysis was used to evaluate the energy demand corresponding to various structural periods and ductility. Finally, the energy demand results were compared and discussed with the existing analytical calculations, as described earlier, in terms of energy factor. The numerical results showed that the energy factors ranged from 0.23 to 0.57 for a strength reduction factor of R = 1.5 to 3, respectively. This finding also suggested further theoretical and numerical studies on the energy factor for the development of energy-based design method.