Since the beginning of additive manufacturing (AM) technologies, 3D printing has proven to be a breakthrough tool in modern manufacturing. Additive manufacturing, particularly Fused Deposition Modeling (FDM), offers unparalleled design flexibility but presents challenges in achieving precise tolerances. As with any new technology, maintaining the dimensional accuracy and precision of 3D printed components brings unique problems, particularly in terms of assembly. This study investigates the prediction of tolerances for 3D-printed components designed for assembly applications. Principles of 3D printing technology were reviewed and the significance of tolerance control in producing precise and functional assemblies is investidated. Next, the challenges of maintaining exact tolerances in 3D printed products are explored, including factors such as material characteristics, printing parameters, and post-processing operations. This research addresses these challenges through systematic experimentation with six types of joints: square shafts, circular shafts, spherical joints, square threads, keyed joints, and spline shafts. Using advanced slicing software and precise calibration of the Elegoo Neptune 4 printer, optimal parameters were established to enhance print accuracy and reliability. Results were analyzed through tabulated data and graphical representations, offering practical guidance for tolerance adjustments based on nominal dimensions and fit types. The study highlights the critical role of design, material selection, and process control in achieving assembly-compatible 3D-printed components. These findings contribute to advancing tolerance analysis in AM, enabling greater applicability of 3D printing for functional assemblies in engineering and manufacturing contexts.