P&L Playbook for eCommerce by ex-SUGAR & Raymond Leader

What Is a Bill of Materials (BOM) in Manufacturing?

The BOM full form in production is Bill of Materials. A bill of materials is a comprehensive list of all components, raw materials, and subassemblies required to manufacture a product. In simple terms, it answers the question: What is BOM in production? It is the recipe or formula that guides manufacturers in producing a finished item.

The bill of materials connects every stage of production, including design, procurement, inventory, and manufacturing. Design teams define product structures, procurement teams utilise BOMs for sourcing, inventory managers track part availability, and production teams follow it for assembly.

A well-structured BOM improves efficiency by ensuring accurate part requirements, reducing errors, and streamlining planning. It prevents shortages, avoids overstocking, and supports better scheduling.

Types of Bill of Materials

A bill of materials (BOM) is not one-size-fits-all. Different industries and functions require different types of BOMs to manage product design, production, sales, and after-sales services. Below are the most common types of BOMs and their specific purposes.

Engineering Bill of Materials (EBOM)

  • An Engineering BOM defines the design of a finished product. 
  • It usually originates from CAD (Computer-Aided Design) drawings and reflects how engineers envision the product. 
  • Multiple EBOMs may be created during product lifecycle management as designs evolve.

Manufacturing Bill of Materials (MBOM)

  • The Manufacturing BOM details all raw materials, parts, and sub-assemblies required on the shop floor to produce a finished item. 
  • It also includes packaging materials to ensure the product is ready for delivery to the customer.

Sales and Configurable BOMs

  • A Sales BOM links finished products directly to sub-items in the sales order. 
  • A Configurable BOM, on the other hand, is designed for customised products. 
  • It outlines components, labelling, and packaging tailored to customer specifications, making it common in industries with product variants.

Service BOMs

A Service BOM supports after-sales needs. It lists parts and assemblies required for repairs, maintenance, and replacements, ensuring smooth product servicing throughout its lifecycle. To learn more about how material planning ties into operations management, see material requirement planning in operations management.

Costed BOMs

A Costed BOM adds financial data to material requirements. Associating costs with each component helps businesses analyse pricing, profitability, and cost control before and during production.

Other specialised BOMs include Production BOMs (the foundation of production orders), Assembly BOMs (sales-focused structures), Template BOMs (flexible models), and Modular BOMs (breaking products into subassemblies for customisation and easier maintenance).

Bill of Materials Example

A bill of materials example illustrates how various components come together to form a finished product. Below is a simple BOM for a wooden chair:

ProductComponentsQuantity
Wooden ChairWooden Legs4
Seat Panel1
Backrest1
Screws12
Wood Glue1 unit
Cushion Cover (optional)1

This bill of materials example demonstrates how each part is listed with its required quantity. In real-world production, such as furniture manufacturing, the BOM ensures every material is accounted for before assembly.

Similarly, in electronics like a smartphone, a BOM would include the display, battery, processor, camera module, and casing. Each component is tracked for quantity, sourcing, and cost. This prevents errors, reduces material shortages, and streamlines the production process.

BOM Format and Structure

A bill of materials (BOM) format is a structured list that outlines all components needed to build a product. Typical BOM fields include part name, ID, description, unit of measure, quantity, cost, and supplier details. This format ensures accuracy in procurement and production planning. 

Depending on the industry, formats may vary. For example, electronics may include version numbers, while furniture may highlight the materials and finishes used.

Single-level Bill of Materials

A single-level BOM lists each part required to build a product, similar to a shopping list. It is simple to create, but it does not show relationships between assemblies and subassemblies. For example, in a car BOM, it won’t break down the door handle into smaller parts, making troubleshooting difficult.

Example: Single-level BOM for a Wooden Table

Part IDComponentQuantity
T001Tabletop1
T002Wooden Legs4
T003Screws12
T004Wood Glue1 unit

Multi-level Bill of Materials

A multi-level BOM (or indented BOM) shows hierarchical relationships between components, subassemblies, and assemblies. Changes in a parent assembly automatically cascade to child components. This makes it the preferred format for complex products, such as vehicles, machinery, or electronics.

Example: Multi-level BOM for a Wooden Table

LevelParent ItemComponentQuantity
0Wooden TableTabletop1
0Wooden TableLeg Assembly4
1Leg AssemblyWooden Leg1
1Leg AssemblyScrews3
0Wooden TableWood Glue1 unit

How to Make a BOM

Creating a bill of materials (BOM) is a structured process that ensures accuracy in production. Here’s a step-by-step guide on how to make a BOM:

Step 1: Define Your Product

Begin by identifying the product and its various versions. For example, a chair may have different BOMs depending on the type of wood or upholstery used.

Step 2: List Components

Include all raw materials, parts, and subassemblies required. For a chair, this may include legs, seat, backrest, screws, and upholstery fabric.

Step 3: Assign Part Numbers

Give each component a unique identifier (SKU or part number) for easy tracking in inventory and procurement.

Step 4: Specify Quantities

Document the exact quantity required for each part, specifying whether it is in unit or batch form.

Step 5: Add Costs

Record unit costs of materials and labour to calculate total production cost. This helps in pricing and cost control.

Step 6: Review and Update

BOMs must be updated regularly as products evolve. Version control ensures everyone uses the most accurate information.

Tools like Excel, ERP systems, and PLM software simplify BOM creation, helping manufacturers maintain accuracy, standardisation, and efficiency.

WareIQ Fulfilment & Shipping Solutions for eCommerce

For growing e-commerce brands, managing inventory, orders, and shipping across multiple channels can be a complex task. WareIQ, a Y Combinator-backed full-stack platform, simplifies this process with end-to-end fulfilment and shipping solutions for D2C, Marketplaces, Quick Commerce, and B2B channels.

With a pan-India network of WareIQ-operated Seller Flex & FAssured-compliant fulfilment centres across 12+ cities, brands can store inventory closer to customers and reach over 27,000 pin codes via reliable last-mile partners.

WareIQ’s multi-channel platform integrates seamlessly with marketplaces (Amazon, Flipkart, Myntra, Nykaa), D2C stores (Shopify, Magento, WooCommerce), WMS, and ERPs. Features like Inventory LogIQ, AI-driven replenishment, and tech-enabled returns QC ensure minimal stockouts, optimised operations, and reduced order disputes.

Brands also benefit from flexible fulfilment capacity, centralised inventory for multiple channels, and access to marketplace programs like Seller Flex & FAssured. With WareIQ, businesses can streamline order management, lower operational costs, and focus on scaling sales rather than logistics.

FAQs

Can a BOM be used for services, not just physical products?

Yes. Service BOMs list the tasks, tools, and resources required to deliver a service efficiently, much like product BOMs list components.

How often should a BOM be updated?

A BOM should be updated whenever there’s a design change, new component, supplier change, or process modification to avoid production errors.

What is the difference between a single-level and a multi-level BOM?

A single-level BOM lists only the immediate components of a product, while a multi-level BOM includes sub-assemblies and their components, showing the full hierarchy.

Can a BOM help with regulatory compliance?

Yes. BOMs track materials and components, which is crucial for industries such as electronics, automotive, and pharmaceuticals that require regulatory documentation.

Is it possible to automate the creation of BOMs?

Absolutely. ERP and PLM software can automatically generate BOMs from CAD designs or product configurations, reducing manual errors and saving time.

Mariyam Jameela
Author

Mariyam Jameela

Mariyam Jameela works as a content writer at WareIQ. With a proven track record of working with renowned brands such as GO Digit, Urban Ladder, Juspay, Hong's Kitchen, and many more. She actively contributes to the creation of blog posts centered on eCommerce operations, fulfillment, and shipping, in addition to providing insights on various strategies and techniques tailored for eCommerce sellers

Read all of Mariyam Jameela's Posts