Häufig gestellte Fragen
What is the difference between MRP and ERP?
MRP (Material Requirements Planning) is a specialised computational method that uses the production programme, bills of materials and inventory levels to determine which material is needed in which quantity by which date. ERP (Enterprise Resource Planning), by contrast, is a company-wide class of systems that integrates this material planning with financial accounting, controlling, human resources, sales and purchasing in a shared database. The core difference lies in scope: MRP answers only the quantity- and schedule-related material question, whereas ERP maps the overall commercial and organisational context. In today's standard systems MRP is therefore not a separate product but a module within the ERP.
Is MRP part of ERP?
Yes, material requirements planning is generally an integral component of modern ERP systems and not a standalone competing product. Established solutions such as SAP S/4HANA, Microsoft Dynamics 365, Sage and Infor already include the MRP logic and extended capacity planning (MRP II) as core functions of their production and procurement scope. Historically, ERP actually evolved from precisely this planning logic, which is why MRP is functionally a subset of what a full ERP system delivers. A separate MRP tool is nowadays usually procured only where an existing system landscape needs particularly powerful, specialised planning.
Which came first, MRP or ERP?
MRP came along well before ERP. Material requirements planning emerged in the 1960s in discrete manufacturing; the IBM engineer Joseph Orlicky is regarded as its defining figure, having comprehensively described the method in his 1975 book "Material Requirements Planning". In the early 1980s, Oliver Wight among others extended the method to MRP II (Manufacturing Resource Planning), adding capacity, resource and in part financial planning. The term Enterprise Resource Planning was only coined around 1990 by the Gartner Group and stands for the generalisation of this idea to all areas of the company.
What does MRP II mean and how does it differ from MRP?
MRP II stands for Manufacturing Resource Planning and is the evolution of classic MRP dating from the early 1980s. While the original MRP exclusively calculates material and quantity requirements from bills of materials and inventory levels, MRP II additionally incorporates capacity and resource planning as well as, in part, financial figures. MRP II thus answers not only the question of which material is needed, but also whether machines, personnel and lead times allow the plan in the first place. In this way MRP II forms the bridge between pure material requirements planning and today's company-wide ERP.
Does a small manufacturer need ERP, or is an MRP tool enough?
That depends on the complexity of the processes and the existing system landscape. If only production planning is to be digitalised and accounting and sales already work well in separate systems, a focused MRP tool with manageable acquisition costs can suffice — for instance with simple make-to-stock production and stable demand. However, as soon as media discontinuities and duplicate data entry between departments cost time, or cross-departmental transparency on orders, liquidity and delivery capability is required, an integrated ERP that includes material planning as a module pays off. As a rule of thumb: as the company grows and variant diversity increases, so does the added value of a full ERP system.
Can an MRP system cover accounting and sales?
No, a pure MRP system covers neither financial accounting nor sales or human resources, but exclusively quantity- and schedule-related material planning. From primary demand, bills of materials and inventory it computes procurement and production proposals, but makes no statements about liabilities, order profitability or delivery dates promised to customers. These commercial and organisational tasks are only handled by an ERP system, which links material planning with all other areas of the company in a unified database. Anyone wanting to interlink accounting and sales with production planning therefore cannot avoid an integrated solution or a clean interface connection.