Abstract: This paper discusses the influence of the precipitate solubility on Gran titration. An equation of the error has been derived from the modified Gran function. The theoretical errors have been calculated for determining chloride of various concentrations. If the titrant (AgNO₃) concentration is 2× 10^-3 M, the determination is suitable in the range of 5×10^-6 M—5 ×10^5-M.In order to improve the sensitivity and accuracy,increment method is suggested for determining the chloride below 5×10^-6M. The limit concentration of chloride for determining is 1×10^-6 M and the coefficient of variation is 20%.