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What Is a Bill of Material List?

bill of material list

In manufacturing, a bill of material list is a document that details the raw materials, assemblies, subassemblies, parts, and components needed to make a product. It also provides instructions for procuring and using the materials.

The BOM is used by multiple departments in a company from the early stages of new product development all the way to the sales stage. It is expected to be as interlinked, multi-leveled, appended, and detailed as possible to streamline production management.


A bill of material (BOM) is a list of raw materials, sub-assemblies, intermediate assemblies, parts, and components that are used to build a product. It is a key tool in production management because it ensures that parts are available when needed and that the assembly process is as efficient as possible.

A BOM is also important for communication between manufacturing partners, which is essential for a successful project. If the BOM is incorrect, it can lead to delays in production or requisitions for missing components. This can cost the company time and money, as well as affect production and the quality of a product.

Parts in a BOM should have a unique number and name, which help people identify and reference the part instantly. This is especially helpful for manufacturers with distributed teams.

It should also have a phase, description, and quantity, which help to clarify the lifecycle of the part and its stage in the development cycle. These stages can be labelled with terms like ‘In Production’ or ‘Unreleased’ for parts in production, and ‘In Design’ for new parts that are not yet approved.

The number of parts that make up a component in a BOM is also important. This helps to guide purchasing and manufacturing decisions, as well as ensure that enough parts are ordered to meet demand.

Often, a bill of materials list will contain CAD drawings and subassembly instructions for certain components. This is an important feature to include as it will ensure that the manufacturer has a clear understanding of how the components should be assembled.

In addition to this, it is crucial that the BOM includes a detailed description of each part or material. This description will enable people to distinguish different parts and materials from one another, which can reduce human error in the production line.

In addition, the BOM should include a BOM level, which is the number that details where a particular part or assembly fits in the hierarchy of the BOM. This makes it easier for anyone who has an understanding of the structure to decipher the BOM quickly and easily.


In the manufacturing industry, a bill of material list is the primary source of information for purchasing raw materials and assembling a finished product. It is essential for ensuring production runs smoothly and minimizes waste. It also provides a detailed inventory of what is needed for a specific project and helps determine scheduling.

In addition to the materials, a BOM lists assembly instructions and any other pertinent data related to the manufacturing process. It also helps to create a single point of reference for any team involved in the project.

Whether you’re constructing a small electronic device or an industrial machine, the BOM is a crucial document. This is because it identifies every component, part and raw material used in the manufacture of your products.

A good BOM should be sensibly organized with a leveled, hierarchical structure. This helps to visualize how parts and components fit into the overall product structure, which makes it easier for engineers and others involved in the project to supervise the design and engineering processes.

The BOM should also have a unique number for each part or assembly, which is designed to make it easy to recognize and refer to a particular part or assembly. Manufacturers will typically number each part or assembly on the BOM, and this helps to ensure that any team member engaged in the manufacturing process can find it quickly.

Another important aspect of a BOM is the quantity of each item listed. Regardless of the scale of your business, it is important to include an exact amount of each part, assembly or material on your BOM. This can save time and resources in the long run because it eliminates misunderstandings and confusion during the manufacturing process.

The BOM should also list suppliers, contact information and lead times for each part or component. This information will help to reduce inventory costs, streamline supply chain processes and decrease production waste. Additionally, it will help to streamline maintenance and repairs. This information can be easily accessed from anywhere in the organization and will enable your maintenance staff to repair more equipment in-house, which reduces costs and increases efficiency.


A bill of material list is an important document that describes the materials required for the construction or assembly of a product. It is a critical tool in the manufacturing process and provides primary data for integrating the product with the company’s enterprise resource planning (ERP), supply chain management, and manufacturing execution systems.

A BOM is a hierarchical listing of the raw materials, sub-assemblies, and components that go into the construction or assembly of a product. They typically include a detailed description of each part, the quantity and cost needed to build it, and instructions for assembly.

There are several types of BOMs, including single-level and multi-level. The type of BOM used depends on the complexity of the construction or assembly.

One-level BOMs are used for products that have simple constructions and require no sub-assemblies. These BOMs are usually created by technical designers or engineers.

Multi-level BOMs are usually used for more complicated constructions. They typically include sub-assemblies that are broken down into more granular levels, and they often have indented levels for each assembly and component.

They also include a note section where the designer can provide additional information that will be useful to anyone who refers to the BOM. This could include alternate suppliers or the specifications that a particular part must meet.

It can be helpful to include a unit of measure such as meter, centimeter, in, or ounce. This will help determine the size and quantity of parts that need to be ordered.

In addition, it is a good idea to include notes about how to order certain parts, the vendor name, and the expected delivery timeframe. These will allow people to quickly find the information they need while still being able to track progress throughout the production cycle.

The BOM is an essential document that should be included in every company’s supply chain management strategy. This is especially true for companies that source their product parts from multiple vendors around the world. By managing from where different parts are sourced, purchasing costs, and quantities needed, companies can reduce their material and logistics costs while maintaining an optimal product schedule.


A bill of materials list is a structure that identifies all the raw materials, components, and assemblies required to produce a product. It can be used to guide the purchase and ordering of materials, and to track production costs and inventory. It can also be used as a tool for quality control and to improve supply chain resiliency.

Regardless of the size of your manufacturing operation, having an accurate bill of materials list is essential to efficient and effective production. It helps you plan purchases, estimate costs, plan for and control inventory, minimize production delays and waste and price products correctly.

The information in a bill of materials can include many different elements, from material descriptions to work instructions and part numbers. Each element should be clearly labeled and unique to the product that it describes. This will make it easy for anyone who needs to reference the BOM to find and identify parts.

There are several types of BOMs, including engineering bills of materials (EBOMs), sales bills of materials (SBOMs) and manufacturing bills of materials (MBOMs). The EBOM is typically developed during resource planning, when the product is still being designed. It consists of the components and sub-assemblies needed to produce the product, along with a technical drawing that shows the final product.

Meanwhile, the SBOM is created after a sales order has been placed by a customer, and it lists all of the components that are needed to develop a product that meets that customer’s specifications. This type of bill of materials is often called a configurable bill of materials, as it identifies the parts and components that are needed to manufacture a product that meets a specific design specification requested by the customer.

There are several benefits to creating a bill of materials list, including increased resiliency in your supply chain and lower overall costs. In addition, an accurate and up-to-date bill of materials list can help you streamline production and cut down on production errors such as shortages or overages in material, production downtime and expediting charges. It can also improve communication and collaboration among team members.