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Bill of Materials Defined

A bill of materials is an important component for a business that operates a manufacturing process. It helps in keeping the operations smooth and prevents delays in production and shipping.

A BOM defines a list of raw materials, sub-assemblies, intermediate assemblies, sub-components and parts along with the quantity required for manufacturing a product. It is a hierarchical structure that includes the finished products at the top level followed by individual components & materials.


A bill of materials (BOM) is a list of all the raw materials, assemblies, sub-assemblies, components and parts required to manufacture a finished product. It may also contain detailed information such as the unit of measure for each item and the quantity needed to produce one unit of a particular product.

It is used to communicate product specifications to manufacturing partners and suppliers. It helps eliminate errors such as ordering the wrong component or quantity of a part, which could result in production delays and costly inventory discrepancies. A well-executed BOM is also useful for estimating costs, planning purchases, and monitoring inventory levels.

The level of detail on a BOM varies depending on the complexity of the product. For example, a BOM for a car might fill several binder pages while a BOM for a chair might fit on a napkin. The structure of a BOM is also important to consider. For example, an engineering BOM is specific to the design process; a manufacturing BOM is specific to assembly and production processes.

A BOM that contains granular and accurate details can be extremely useful in streamlining the manufacturing process. This is especially true when dealing with a high volume of orders and complex products. For example, if a manufacturer is creating a new pair of blue jeans, the details of the BOM can include fabric kind, weaving arrangement, cutting and sewing guidelines and labeling specifications.


A bill of materials is a comprehensive structured list of all the components, raw material assemblies and parts that go into a product. Also referred to as a production recipe or assembly component list, it includes procurement instructions and is the foundation of seamless production processes. A BOM helps reduce waste and ensures that the correct components are used in each production run. This increases manufacturing efficiency, reduces operating costs and boosts supply chain resiliency.

For example, a BOM for a pair of blue jeans could include the fabric type, weave arrangement, cutting and sewing guidelines, labels and safety stickers. This information allows the manufacturer to produce an accurate blueprint for each pair of jeans. The company can then use the same template for future runs of the same design to minimize inventory inaccuracies and production delays.

While the purpose of a BOM is clear, there are several different types of BOMs and how they are used. The most common is a finished goods BOM. This type of BOM focuses on the individual parts that make up a product and enables businesses to track their costs. This information is important when setting prices for finished products and estimating production costs. It can also help companies identify & organize the logical components of their products, making them easier to build & test.


The first step in creating a bill of materials is to provide a complete list of all the components needed to make a finished product. This includes everything from raw materials to specialized equipment. It also includes any additional assembly, sub-assembly or finishing work. According to Form Labs, a digital fabrication company, this can include things such as cutting and sewing guidelines for a pair of jeans or welding guidelines for a metal part.

The next step is to determine how to organize the list. It’s important to include a hierarchy to help everyone understand the relationship between each component. This can be done through a numbering system or by grouping parts and assemblies into categories. It’s also useful to use color coding to highlight different types of materials or parts.

Once a BOM is complete, it can be shared with suppliers to make the purchasing process more efficient. This will save time and money by eliminating errors that could result in delays in production or higher operating costs.

Another benefit of using a BOM is that it allows manufacturers to track each item as it goes through production. This ensures that it is being used appropriately and that there are no unauthorized alterations. It also helps reduce waste and rework by providing a clear path for each stage of production.


A bill of materials (BOM) is a detailed list of raw materials, components, sub-assemblies, and pieces used to make a finished product. It includes the item number, description, and quantity required for each component in an assembly or sub-assembly. A BOM can be used by engineers to design a product, manufacturing teams to determine the amount of material needed for production, and stores teams to place orders for the necessary components.

A BOM is a key part of any manufacturing process and is vital for businesses that sell their products directly to customers. A BOM can be used to track all the components that are needed to build a finished product, and it can also be used to create a quote for a customer.

The most common types of BOMs are engineering and manufacturing BOMs. An engineering BOM is typically created using a computer-aided design (CAD) system and is intended to define the structure of the finished product. It is similar to a product specification but differs in that it provides more details about the specific design of the finished product, such as the dimensions, tolerances, and specifications.

A manufacturing BOM is a list of the raw materials, components, and assemblies that are needed to build a finished product. It can be used to manage inventory levels and ensure that all parts are in-house before the start of the manufacturing process. This helps minimize inventory inaccuracies and production delays, which can cost businesses money and reduce the quality of their products.