Managing universal design process is a highly complex and challenging design task due to its multi-parameter characteristics. It becomes even more difficult while accommodating the needs of people with diverse impairments in architectural design process. Thus, this study aims to propose the development and implementation of an innovative computer-assisted universal design plug-in tool (CAUD) in the initial design phase that is compatible with the existing three-dimensional design software, SketchUp. Based on the theories and researches, the cognitive design strategies are analyzed for the efficiency of the knowledge support of the CAUD plug-in tool. Thus, the capabilities of the plug-in tool are defined according to the accommodation with an ideal cognitive strategy during analysis, synthesis and evaluation operations. Moreover, to achieve challenges of selecting the right set of universal design requirements within the plug-in tool, a prioritization technique that is based on the hybridization of the two techniques, the Planning Game (PG) and Analytic Hierarchy Process (AHP) using a cost-value approach is proposed. Through the proposed hybrid technique, requirement–design relationships are computed and the cost-value ratios of requirement priorities are represented. The study that is developed for universal kitchen design applications yielded a significant contribution to the universal design problem-solving process in a computer-aided design (CAD) environment. Finally, the results of the acceptability studies also showed that the CAUD plug-in tool is found in general useful, understandable, efficient, helpful and satisfactory.