Additive manufacturing has been established as a process to produce structural and load-bearing parts, and this process has become attractive to many industries such as medical, aerospace, automotive, and oil and gas. These industrial applications are commonly characterized by high and stringent regulatory requirements. Due to the disparity and lack of consensus in mechanical properties reported in the literature, and the need to test and validate the components manufactured by the additive manufacturing process, this work aimed at performing an experimental simulation study of the effects of the slimness ratio on the mechanical properties of as-built Ti-6Al-4V electron beam additively manufactured parts subjected to tensile tests. From the obtained results, we propose an accurate method for the prediction and correlation of mechanical properties of specimens with different geometries. The main conclusion from this study is that elongation at fracture and tensile toughness follow a logarithmic equation and that symmetric cross-section specimens show superior mechanical strength with similar mechanical behavior to high-stress-triaxiality parts subjected to tensile tests. The fracture mode and associated micromechanisms are strongly influenced by the specimen's width/thickness ratio, and the use of the Bertella-Oliver equation coupled with finite element method (analysis) tools was effective toward understanding the mechanical behavior of specimens subjected to tensile tests. In summary, the method presented here may be useful for predicting and comparing the data of specimens that do not comply with normative values.