This paper studies the computerized tooth profile generation of involute gears cut with pinion-type cutters. Based on the theory of gearing the mathematical models of generating cutters and generated external and internal gears with involute teeth are given. Effective limits of design parameters that determine the actual tip circle radii of the generated gears are investigated. Computer simulation programs are developed to obtain graphs of generating tools and generated teeth surfaces. The effect of tool parameters on generated gear can be investigated before manufacturing.