Abstract: A system for calculating low-level codes (LLCs) for items in a bill of material (BOM) includes a database (301) for storing BOMs; a data obtaining unit (303) for obtaining BOMs from the database; an LLC setting unit (305) for setting LLCs for items; and a data analyzing unit (307) for determining whether an item exists in designated columns in a BOM. A related method for calculating LLCs for items in a BOM includes the steps of: (a) setting an initial value of a variable N as zero, and setting all LLCs for items in the BOM as vacant; (b) reading a first item in the BOM; (c) determining whether the item exists in a child item column of the BOM; (d) setting the LLC of the item as zero if the item does not exist in the child item column; and (e) setting LLCs for other items in the BOM.