A procedure and a simple formula have been developed for determining the maximum allowable plating unfairness tolerance in ship panels. The formula is based on reliability assessment of strength of unstiffened plates having initial imperfections. Plate ultimate strength is determined by taking into account the effects of initial deflections and residual stresses. A series of plate reliability analyses relative to the ultimate strength failure, for varying plate unfairness, and aspect and slenderness ratios, is carried out. Based on the computed results, a simple expression for predicting the maximum allowable unfairness tolerance of the plate is derived. The developed expression, described in terms of the plate slenderness ratio, can be useful for the assessment of unfairness limits of plating between frames in ship structures.