Section 1 of 7

The Warehouse Structure: From Warehouse Number to Quant

Why WM exists on top of Inventory Management

SAP Inventory Management (IM) already knows how much of a material you have in a storage location — say, 500 units of part X in plant 1000, storage location 0001. What IM does not know is where in the building those 500 units physically sit. Warehouse Management (WM) adds that missing layer: it manages stock down to the individual storage bin, so you can direct a forklift driver to the exact shelf. If you have a big warehouse with thousands of bins, IM alone is not enough — WM is what turns "we have it somewhere" into "it is in aisle 12, rack 4, level 2".

The structure, top to bottom

The WM organisational structure is a strict hierarchy. Learn it in order, because every transaction references these levels:

Warehouse number — the top node. One warehouse number represents one physical warehouse complex (a building or site) and is the entry point for all WM activity. It is linked to one or more plant / storage-location combinations.
Storage type — a physical or logical area within the warehouse with its own characteristics: high-rack storage, bulk/block storage, shelf/small-parts storage, picking area, goods-receipt zone, goods-issue zone. Each storage type has its own putaway and stock-removal rules.
Storage section — a subdivision of a storage type used to group bins, often by speed (fast-moving vs. slow-moving) or by criteria like hazardous vs. non-hazardous. It refines where within a storage type something goes.
Storage bin — the smallest addressable location: a single shelf slot or floor position with a unique coordinate (e.g. 01-02-03). This is the level WM directs people to. Storage bins are master data you create individually or generate in bulk.
Quant — the stock of one material with the same characteristics (same batch, same status) sitting in one storage bin. If two different batches of the same part share a bin, they are two quants. The quant is how WM tracks "what exactly is here and how much".

Putting it together

A simple way to remember it: warehouse number is the building, storage type is the room, storage section is the zone in the room, storage bin is the exact shelf, and the quant is the actual stock sitting on that shelf. Every putaway and every pick is ultimately the system deciding which bin, and creating or consuming a quant there.