Bill Of Materials
What is a Bill of Materials (BOM)?
A Bill of Materials (BOM) is a comprehensive list of all the components, parts, raw materials, and sub-assemblies required to manufacture a product, along with their quantities and relationships.
Synonyms: Product Structure, Parts List, Product Recipe, Assembly List, Ingredient List

Why a Bill of Materials is Important
A Bill of Materials (BOM) is crucial for product managers and manufacturers as it serves as a single source of truth for product composition. It helps in accurate cost estimation, inventory management, and streamlined production processes. A well-maintained BOM ensures that all necessary components are accounted for, reducing the risk of production delays or errors.
How a Bill of Materials is Used
Product managers use BOMs throughout the product lifecycle:
- Product Development: To define and track all components needed for a new product.
- Cost Analysis: To calculate the total cost of materials and identify areas for cost reduction.
- Procurement: To order the correct quantities of materials and components.
- Production Planning: To ensure all necessary parts are available before starting production.
- Quality Control: To verify that the correct components are used in the manufacturing process.
Types of Bill of Materials
There are several types of BOMs used in product management:
- Engineering BOM (EBOM): Used during the design phase, focusing on the product's technical specifications.
- Manufacturing BOM (MBOM): Tailored for the production process, including packaging and assembly instructions.
- Configurable BOM: Used for products with multiple variants or customizable options.
- Service BOM: Lists components needed for product maintenance and repair.
Frequently Asked Questions
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What's the difference between a BOM and a parts list?: A BOM is more comprehensive, including quantities, relationships between components, and often costs, while a parts list is typically just a simple inventory of components.
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How often should a BOM be updated?: BOMs should be updated whenever there's a change in product design, component substitution, or manufacturing process to ensure accuracy.
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Can software products have a BOM?: Yes, software products can have a BOM, often called a Software Bill of Materials (SBOM), which lists all components, libraries, and dependencies used in the software.
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What tools are used to manage BOMs?: Product Lifecycle Management (PLM) systems, Enterprise Resource Planning (ERP) software, and specialized BOM management tools are commonly used to create and maintain BOMs.