The relation between the error in interdetector volume determination and peak spreading was studied for a polymer sample whose molecular weight distribution obeys the log-normal function. A compensation of these quantities was shown, i.e. their values were found for which the ratio of weight- to number-average molecular weight, <(M)over bar (w)>/<(M)over bar (n)>, was constant. The influence of non-uniformity in the molecular weight of the sample on the compensation is demonstrated.