What is Bill of Materials (BOM)

A Bill of Materials (BOM) is a detailed list of all the raw materials, components, parts, and assemblies needed to build a finished product. It’s essentially the recipe that manufacturers and engineers use to plan, order, and assemble products.

Examples

Example Description
Furniture manufacturing A BOM lists every wood panel, screw, fabric piece, and finishing material needed to build a chair.
Electronics assembly A BOM details every circuit board, resistor, capacitor, and connector for a smartphone.
Food production A BOM includes ingredients, packaging materials, and labels needed to produce a batch of cookies.

A brief history

BOMs have been around as long as manufacturing. At first, they were simple paper lists or spreadsheets, manually updated and passed between departments.

In the 2000s, BOMs moved into digital tools, integrated with design, manufacturing, and inventory systems. This made it easier to manage complex assemblies, track changes in real time, and avoid costly mistakes. Today’s BOMs are often dynamic documents linked to CAD files, ERP systems, and procurement workflows.

Good to know

A BOM isn’t just a parts list. It’s a living document that supports product design, production, and procurement. It helps teams stay aligned on what’s needed, when, and in what quantities. For complex products, multiple BOM versions might exist for engineering, manufacturing, and service purposes. Accuracy and version control are critical to avoid delays, cost overruns, and quality issues.

Know more

Frequently Asked Questions

What’s the difference between a BOM and a parts list?
A BOM is more detailed and structured, often including quantities, part numbers, descriptions, and assembly instructions, whereas a parts list is a simpler inventory of components.
How is a BOM used in manufacturing?
In manufacturing, a BOM guides purchasing, production scheduling, and assembly processes to make sure all necessary materials and parts are available at the right time.
Can BOMs change during production?
Yes, BOMs often evolve through Engineering Change Orders (ECOs) to reflect design updates, substitutions, or improvements.
What tools help manage BOMs?
Common tools to manage BOMs include Product Lifecycle Management (PLM) software, Enterprise Resource Planning (ERP) systems, and specialized BOM management software that integrates with CAD and supply chain systems.
Is a BOM only relevant for manufacturers?
BOMs are mostly relevant for manufacturers, but they can also be important for repair services, distributors, and anyone involved in product assembly or maintenance.