Example of a Bill of material form

A Bill of Material (B.O.M.) is a hierarchical list of materials (components, subassembles, ingredients..) required to produce an item, showing the quantity of each required item. Other information such as scrap factors may also be included in the BOM for use in materials planning and costing.

An engineering BOM represents the assembly structure implied by the parts lists on drawings and drawing tree structure. A manufacturing BOM represents the assembly build-up the way a product is manufactured.

A bill of material software package can help you generate labor, overhead, material and outside services in a detailed estimate. It is often a part of the MRP (manufacturing resource planning) and accounting software system.