Bedarfsmenge
Also: Bedarfsmengen, Bedarf, Materialbedarf, Mengenbedarf
AI-generated
The demand quantity refers to the quantity of an item required at a specific point in time or within a planning period. It forms the basis for ordering decisions, inventory planning, and production planning.
Key facts
- The demand quantity specifies how much of an item is needed within a given time period or by a specific date.
- Gross demand and net demand differ in whether existing stock levels and open incoming deliveries have already been deducted.
- Errors in the demand quantity directly lead to excess stock or shortfalls and affect delivery capability.
- In modern ERP and WMS systems, the demand quantity is derived automatically from orders, bills of materials, or forecast data.
- A safety buffer added to the demand quantity can offset delivery fluctuations, but increases capital commitment.
What is the demand quantity?
The demand quantity specifies how much of a particular item is needed within a defined time period or by a specific date. It is a central planning parameter in procurement, inventory management, and warehouse logistics, and arises either from concrete orders (order-driven demand) or from forecasts and planning specifications (plan-driven demand). Without a reliable demand quantity, neither meaningful order quantities can be calculated nor warehouse capacities realistically planned.
Gross and net demand: The difference in practice
In operational inventory management, a distinction is made between gross and net demand. Gross demand encompasses the total quantity required without taking into account existing stock levels or open incoming deliveries. Net demand is derived by subtracting the available inventory as well as already booked but not yet received deliveries from the gross demand. It is generally the net demand that triggers a procurement process.
Safety demand also plays a role: to buffer against delivery fluctuations or forecast errors, the calculated demand quantity is often increased by a safety margin. How large this buffer should be depends on the vendor and the company, and is influenced by factors such as supplier delivery reliability and the criticality of the item.
What matters in planning
The quality of the demand quantity depends directly on the underlying data. Key influencing factors include:
- Up-to-date master data, in particular consumption histories and bills of materials
- Planning horizon and granularity of the sales forecast
- Consideration of scrap, shrinkage, and minimum shelf life
- Coordination between sales, production, and procurement
In ERP and WMS systems, the demand quantity is usually derived automatically from orders, bills of materials, or planning recipes. Nevertheless, a manual plausibility check is advisable, especially in cases of seasonal fluctuations, new items, or irregular consumption patterns. Errors in the demand quantity lead either to excess stock and increased storage costs or to shortfalls and delivery delays — both of which have a direct impact on delivery capability and capital commitment.
Related terms
- ABC-Analyse
ABC analysis is a method for classifying items, vendors, or processes into three priority classes (A, B, C) based on their economic significance. It forms the basis for differentiated decision-making in warehousing, inventory management, and procurement.
- Absatzplanung
Sales planning refers to the systematic forecasting of future sales volumes for defined products, regions, or channels. It forms the foundation for all downstream planning processes in production, procurement, and logistics.
- Absatzprognose
The sales forecast estimates future demand for products or items over a defined period. It forms the basis for inventory, capacity, and procurement planning in logistics and purchasing.
- Artikel
An item is the smallest uniquely identifiable unit in warehousing, procurement, and ERP – described by master data such as name, dimensions, weight, and identification numbers. It forms the basis for planning, order picking, and inventory management.
- Artikelstammdaten
Item master data refers to the permanently valid base data of an item – such as dimensions, weight, packaging units, hazardous goods classification, and best-before date relevance. It forms the foundation for all logistical, procurement-related, and system-driven processes along the supply chain.
- Bedarfsermittlung
Requirements planning refers to the systematic process by which an organization's future material or goods requirements are determined in terms of quantity and timing. It forms the basis for inventory management, procurement, and warehouse planning.
- Kommissionierung
Order picking is the process of assembling individual items from warehouse stock to fulfill a specific customer order — the most labor-intensive step in the warehouse.