Direct answer. Slotting is the method used to determine, for each stored reference, the most relevant location in the warehouse, based on its turnover, weight, volume, or the items it is often ordered alongside, with the aim of reducing distances traveled during picking and optimizing the use of storage space.
How slotting works in practice
Slotting answers a simple but structural question: where should what go? A poorly designed layout forces pickers to travel long distances for high-turnover references, which directly weighs on picking productivity, already identified as a warehouse's top cost item. Conversely, good slotting brings high-turnover references (often classified as “A” in an ABC/Pareto analysis) closer to shipping areas or picking stations, and reserves more distant or higher-up locations for low-turnover references.
Several criteria come into the equation: order frequency, weight and volume (heavy loads placed low for safety and ergonomics), compatibility between products (avoiding storing incompatible references together), and frequent order associations (two references often ordered together benefit from being close by). Slotting is not fixed: periodic re-slotting, generally driven by the WMS based on stock-movement data, allows the layout to be adjusted to actual sales and seasonal changes.
Slotting is distinct from addressing: addressing is the coding system used to precisely locate a spot (aisle, bay, level), while slotting is the strategy that decides which reference occupies which location.
A layout optimized through slotting also makes it easier to automate pallet transport between zones: the robot adapts to any warehouse organization, including after a re-slotting, with no infrastructure work to redo. Explore the autonomous pallet truck or contact us to discuss it.
FAQ
What is the difference between slotting and addressing?
Slotting decides which reference should occupy which location, based on its turnover, weight or order associations. Addressing is the coding system (aisle-bay-level) used to physically locate that spot. The two are complementary and managed together through the WMS.
How often should a warehouse's slotting be redone?
There is no universal frequency: it depends on seasonality and how volatile the catalog is. Many warehouses run a global re-slotting once or twice a year, supplemented by ad-hoc adjustments whenever a turnover spike or a new high-volume product is identified.
Related terms
Location addressing · Picking · Cycle counting · Turnover rate · Occupancy rate · SKU · Warehouse / logistics platform.
See also: warehouse picking methods.
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