Warehouses are almost never full. They are aisle-limited, height-limited or slab-limited, and the difference between those three is the difference between a layout change, a racking change and a new building. Most operators discover which one they have the expensive way.
Pallet positions. Not square metres, not cubic metres, not shelves. A pallet position is one pallet-sized space on a beam level, and it is the unit racking is quoted in, priced in, insured against and — as it happens — inspected by the size band of.
Counting them is arithmetic, not estimation: bays across, beam levels up, pallets per level. The pages below work through that and the four constraints that stop the number going any higher.
Clear height decides how many beam levels fit. Aisle width is set by your trucks, and aisles are the single largest consumer of floor area in a selective layout. The floor slab decides what can be bolted down and how heavily it can be loaded. And your inbound and outbound flow decides how much floor has to stay empty for staging.
Change any one of those and the storage number moves — which is why a capacity problem is usually a layout problem, and only occasionally a building problem.
Once the layout is settled, how the space is worked day to day is a separate discipline: warehouse operations and efficiency.
11 guides
A pallet position is the space one standard pallet occupies in your racking, at rest, in one location. It is the unit every capacity number in this silo is built from, and it is the unit your racking supplier, your 3PL and your insurer are all secretly using even when they talk about square metres.
Storage capacity is not a square metre figure and it is not a guess — it is a multiplication you can do on paper before you touch a tape measure. This is the method, worked through with a hypothetical layout so you can run the same steps on your own numbers.
In a selective racking layout, aisles are usually the single biggest consumer of floor area — more than the racking itself. The aisle width is not a layout preference you set; it is a number your forklift manufacturer publishes for the specific truck and mast you run, and it sets almost everything else about how dense your layout can be.
Clear height is the usable vertical space above the floor once everything else that has to live up there has taken its share. It is almost always meaningfully less than the roof height on a building spec sheet, and it is the number that actually sets how many beam levels your racking gets — which is a direct multiplier on pallet positions.
The slab is the one part of the building that is genuinely expensive to change once racking is installed on it, which makes it worth understanding before the layout is finalised rather than after. Three things about a slab matter for warehouse planning: whether racking can be bolted to it, how flat it is, and what it can carry.
A lease is priced mostly on floor area, but what you are actually paying for is a volume — floor area times clear height. Cubic utilisation is the measure of how much of that volume is doing useful work, and it is frequently the gap between a warehouse that "feels full" and one that has plenty of room left, three or four metres above head height.
Slotting is the decision of which SKU lives in which pallet position, and getting it wrong is one of the most common reasons a warehouse feels out of space when it is not. Before spending on more racking, more height or more floor, re-slotting is usually the cheapest large improvement available, because it changes nothing about the building and everything about how it is used.
Every square metre of a warehouse floor plan tends to get claimed by racking or aisles first, because that is where the pallet position count comes from. Dock and staging space is the floor that has to be left deliberately empty for goods in transit, and forgetting to plan for it properly is one of the more common ways a layout that looks right on paper fails on day one.
FIFO and LIFO describe the order stock has to move in, not just a warehouse process preference — and that requirement rules certain racking systems in or out before cost or density even enter the conversation. Get the rotation requirement wrong at the layout stage and no amount of clever slotting fixes it afterwards.
A warehouse that "needs more space" is a real problem, but the fix is not always a bigger building. There is a rough order of options worth working through, cheapest and least disruptive first, because a genuinely full building is rarer than it looks and most of these options recover capacity from a building you already have.
We are not going to give you a number. Anyone who quotes a per-bay price without seeing your floor, your height and your pallet is guessing, and the guess will be wrong in whichever direction suits them. What we can do is tell you what the price is made of, so you can read a quote properly.