This article examines the possibility of determining the optimal amount of inventory for an assembly line with a small number of parts. The optimization process is done using linear programming methods, specifically the enumerative method, and its results are compared by an approximation method that does not require such a number of iterative steps. The procedure of creating a purpose function defined conditions of solvability of the task and subsequently determined the total optimal size of parts stocks and also the size of stocks of individual parts before the actual start of assembly is explained. This procedure is applicable to a small number of variable parameters.