Four lot-sizing heuristic rules are presented that are truly simple and at the same time independent of economic order quantity (EOQ) assumptions. These rules are tested and compared against the Wagner-Whitin rule, an optimization rule based on dynamic programming, through the use of computer simulation. It is found that under a variety of tested environments some of the heuristics, despite being naive, are surprisingly effective in reducing the total cost. It is suggested that material requirements planning should give more consideration to simple lot-sizing heuristics.