What is ABC slotting?

Ranking products by how often they are picked and storing the A items — the fast movers — in the most accessible places. A small share of SKUs usually carries most picks: about 15% of products and 85% of turnover in one study.

What is the golden zone in a warehouse?

The band around waist to elbow height, where items are quickest and safest to pick. The Georgia Tech textbook puts popular and heavy items there; OSHA advises high-volume items near standing elbow height.

How often should a warehouse re-slot?

Whenever the pick ranking has shifted enough that fast movers sit in slow locations. No standard sets a schedule; the measure to watch is how far pickers travel.

Term

Slotting

Slotting is deciding where each product is stored in a warehouse, so fast movers sit where they are quickest to pick. The usual method ranks products by how often they are picked: in one widely cited study, the fastest class held about 15% of products and 85% of turnover. Popular items go at waist height.

Also called warehouse slotting, slotting optimisation, ABC slotting, golden zone, re-slottingUpdated 13 October 2026

Why location matters

Travel is the biggest part of an order picker's day. De Koster and colleagues' review in the European Journal of Operational Research shows a typical split, after Tompkins: travel 50%, search 20%, picking 15%, set-up 10%, other 5%. Every metre a fast mover sits from the dispatch area is walked again on every pick. The same review estimates order picking at as much as 55% of total warehouse operating expense — the cost slotting works on. The Georgia Tech textbook defines slotting as the careful placement of individual cases within the warehouse.

How it is done

Rank SKUs by picks, not by stock held — the review suggests 2 to 4 classes in practice.
Put the fastest class nearest the pick path's start and end.
Within a bay, put popular and heavy items at waist level, the golden zone; OSHA's warehousing guidance also says to place high-volume items near standing elbow height.
Review the ranking as demand changes, and move what has moved.

Worked example: 2,000 SKUs

2,000 SKUs × 15% = 300 fast movers carrying about 85% of picks · a picker's 8-hour shift at 50% travel = 4 hours walking · cut travel by 20% → 48 minutes back per picker per shift

The 15/85 and 50% shares are from the de Koster review; the 20% cut is illustrative.

The mistake people make

Packing every fast mover into one aisle. The Georgia Tech textbook warns to avoid creating congestion by concentrating popular items too much — pickers queuing in the golden aisle can give back the walking time the slotting saved.

FAQ

Slotting: common questions

What is ABC slotting?: Ranking products by how often they are picked and storing the A items — the fast movers — in the most accessible places. A small share of SKUs usually carries most picks: about 15% of products and 85% of turnover in one study.
What is the golden zone in a warehouse?: The band around waist to elbow height, where items are quickest and safest to pick. The Georgia Tech textbook puts popular and heavy items there; OSHA advises high-volume items near standing elbow height.
How often should a warehouse re-slot?: Whenever the pick ranking has shifted enough that fast movers sit in slow locations. No standard sets a schedule; the measure to watch is how far pickers travel.