SAP Bill of Materials
The SAP bill of materials shows which components a product consists of and is central to planning, demand forecasting and efficient manufacturing in SAP S/4HANA.
Structure, functions and significance in the SAP system
The SAP bill of materials is a key element in production planning and materials management. It provides a structured description of the components that make up a product or assembly, and the quantities required. Without bills of materials, automated production planning, material requirements planning or costing in the SAP system would be virtually impossible.
The bill of materials plays a particularly central role in SAP S/4HANA, as it is closely linked to other master data such as the material master, work plans or production orders. Companies can use it to map complex products transparently and manufacture them efficiently.
What is an SAP bill of materials?
An SAP Bill of Materials (BOM) is a structured list of all components, assemblies and materials required to manufacture a product. It typically contains:
- the header material (the finished product or an assembly)
- the component materials
- the quantities required
- units of measure and, where applicable, other attributes
It thus forms the basis for production processes and materials planning.
Example of a simple bill of materials
| Product | Components | Quantity | Unit |
| Bike | Frame | 1 | Piece |
| Bike | Wheel | 2 | Piece |
| Bike | Brake | 2 | Piece |
| Bike | Saddle | 1 | Piece |
In complex products, bills of materials are often structured in multiple levels, as assemblies themselves consist of further individual parts.
How is a bill of materials structured in SAP?
A bill of materials generally consists of two main sections:
1. BOM header
The BOM header contains basic information about the end product or assembly.
Typical data in the BOM header:
- Material number
- Plant
- BOM usage
- Base quantity
- Validity date
- Revision number
This data uniquely identifies a BOM in the SAP system.
2. BOM items
The line items contain the individual components of the product.
The most important information includes:
- Component material
- Quantity required
- Unit
- Line item number
Multi-level bills of materials make it possible to represent complex product structures, as assemblies in turn have their own bills of materials.
What types of SAP bills of materials are there?
SAP supports various types of bills of materials, which are used depending on the application.
| Bill of materials type | Description |
| Bill of materials | Most common form, describes the components of a material |
| Document bill of materials | Links documents or drawings |
| Equipment bill of materials | Used in the maintenance of machinery |
| Bill of materials for the functional location | Illustration of plant layouts |
| Order bill of materials | For bespoke manufacturing |
| Project bill of materials | Use in project structures |
This flexibility allows bills of materials to be used in different areas of the business.
What role does the bill of materials play in production?
In production planning, the bill of materials is an indispensable element. It is used in various processes:
Material Requirements Planning (MRP)
The bill of materials serves as the basis for the automatic calculation of material requirements.
Example:
- To make 100 bicycles, you need: 100 frames, 200 wheels, 200 brakes
SAP berechnet daraus automatisch den Bedarf für Einkauf oder Produktion.
Production orders
When a production order is created, the bill of materials is automatically copied.
This means that SAP knows exactly:
- which materials are required
- what quantities will be used
- which assemblies need to be assembled
Costing and cost planning
Product costing is also based on the bill of materials, as it defines the material requirements.
Key SAP transactions for bills of materials
There are standard SAP transactions for maintaining bills of materials.
| Transaction | Function |
| CS01 | Create a bill of materials |
| CS02 | Modify the bill of materials |
| CS03 | View bill of materials |
| CS11 | Single-level BOM explosion |
| CS12 | Multi-level BOM explosion |
| CS15 | Display the use of a bill of materials |
These transactions are part of the SAP PP (Production Planning) module.
Bills of materials in SAP S/4HANA
SAP S/4HANA has modernised numerous functions, particularly in terms of user interfaces and data processing.
Key new features:
1. Fiori Apps
In addition to traditional transactions, modern SAP Fiori apps are available, such as:
- Manage Bills of Material
- Display Material BOM
- Change Material BOM
These apps offer:
- intuitive operation
- faster navigation
- better visualisation of complex bills of materials.
2. Real-time analysis
Thanks to SAP HANA’s in-memory technology, bills of materials can be analysed more quickly, for example for:
- Material requirements planning
- Production simulations
- Variant configuration
3. Integration with digital production processes
Today, bills of materials are often integrated with:
- Engineering Change Management
- Production Planning
- Supply Chain Planning
This creates a seamless flow of data from design through to production.
Different types of bill of materials structures
Depending on the view, bills of materials can be structured in different ways.
| Typ | Description |
| Single-level bill of materials | Only the direct components of a product |
| Multi-level bill of materials | Assembly comprising further sub-components |
| Modular bill of materials | Display of the immediate components of an assembly |
| Structural bill of materials | Hierarchical representation of the entire product structure |
These structural variants allow for the flexible representation of complex products.
Integration of the bill of materials into other SAP modules
An SAP bill of materials is closely linked to other SAP modules.
| SAP Modul | Link to the bill of materials |
| SAP PP | Production planning and work orders |
| SAP MM | Procurement and stock levels |
| SAP SD | Variant configuration in Sales |
| SAP PM | Spare parts and maintenance |
| SAP CO | Product Costing |
Thanks to this integration, a bill of materials created once can be used throughout the organisation.
Best practices for maintaining SAP bills of materials
A properly maintained bill of materials is crucial for stable production processes.
Typical challenges:
- missing components
- incorrect quantities
- duplicate bills of materials
- outdated versions
Recommended measures:
- Clear master data processes
- Version and change management
- Regular data checks
- Use of approval workflows
FAQ – Frequently Asked Questions about SAP Bills of Materials
What is an SAP bill of materials?
An SAP bill of materials is a structured list of all the materials and assemblies required to manufacture a product.
What information does a bill of materials contain?
Typical content includes:
- Header data
- Component materials
- Quantities
- Units of measure
- Validity dates
- Plant
Where are bills of materials used in SAP?
Bills of materials are primarily used in:
- Production planning
- Material requirements planning
- Cost calculation
- Maintenance
- Project management
What is the difference between a single-level and a multi-level bill of materials?
- Single-level: displays only the direct components of a product
- Multi-level: displays complete assembly structures
What role does the bill of materials play in SAP S/4HANA?
In SAP S/4HANA, the bill of materials remains a key master data structure and is enhanced through modern Fiori interfaces, real-time analytics and integrated production processes.
Fazit
The SAP bill of materials is a fundamental component of production planning, materials management and cost accounting. It ensures that companies always know:
- what materials are required
- how much of each is used
- how products are structured.
Thanks to its integration with various SAP modules and the enhancements in SAP S/4HANA, the bill of materials remains a key component of digital production processes and an efficient supply chain.
