Selective Laser Sintering is one of the many technologies that can be applied when is wanted to print something in 3D. This additive manufacturing process is not only used for rapid prototyping but as well for final goods, so the quality of the piece is very important. The aim is to analyze the dimensional tolerances of different prototypes printed using the selective laser sintering technology, employing a benchmark process, comparing the dimensions of the geometries as well as their measures, by means of the IT Grades and the ISO basic sizes. Many geometries were studied: cylinders, cones, planes, tilted planes, angular planes, polygons, etc.