Abstract: Extensive numerical experiments on the long-term dynamics of planetesimal disks with planets in systems of single stars have been carried out. The planetary chaotic zone clearing timescales (Formula presented.) as a function of mass parameter (Formula presented.) (planet–star mass ratio) have been determined numerically with a high accuracy separately for the outer and inner parts of the chaotic zone. Diffusional components (Formula presented.) have been revealed in the dependence (Formula presented.). The results obtained are discussed and interpreted in light of existing analytical theories based on the mean motion resonance overlap criterion and in comparison with previous numerical approaches to the problem.