How to label warehouse locations

This is the advice we'd give someone who told us they were never going to buy anything from us, and it's the one that turned up most consistently in the data. Label your locations properly before you do anything else.

The five rules

1. Read it the way a person walks. Aisle, then bay along the aisle, then level up the rack: A-04-2. Not level-first, not by rack manufacturer part number, not by whatever the shelving supplier stencilled on it.

2. Same number of characters, always. A-04-2, never A-4-2. The day you export to a spreadsheet or a system, A-10 sorts before A-4 and your sequence is silently scrambled. This one costs nothing at the start and is miserable to retrofit.

3. Put the label on the beam at eye level, not on the product. Products leave. Beams don't. A label on a tote is a label that walks out the door in six weeks.

4. Odd aisles on one side, even on the other, and mark the direction at the end of each aisle. A new picker should be able to find A-12 without asking anyone. That's the entire test.

5. Leave gaps in the numbering. Number bays 10, 20, 30 rather than 1, 2, 3. When you split a bay in two next year — and you will — you get 15 instead of relabeling the aisle.

What to print on

Anything laser-printed on plain paper and taped will survive about four months in a working aisle, less near a dock door. Self-adhesive polyester labels cost more per label than you'd like and outlast the racking. Black on yellow reads from further away than black on white, and it matches what people already associate with 'pay attention here.'

Print at least twice the size you think you need. The person reading it is walking, carrying something, and it may be January with the dock door open.

How long it takes

A 12,000 square foot operation with a few hundred pick faces is a weekend for two people, most of which is walking. The design decisions above are twenty minutes. Getting them wrong is the part that costs a year.

What changes afterwards

Training a new picker stops being a tour and starts being a sentence: the code on the sheet is where the thing is. Counting stops requiring the person who knows the building. And if you do eventually put in software, it inherits a warehouse that already tells the truth, rather than becoming an expensive record of where things used to be.