Rack Capacity Calculator

Honeycombing costs a fifth of nominal capacity.

Honeycombing costs a fifth of nominal capacity. Honeycombing is the empty space left when a partly-emptied position cannot take another SKU.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Racking bays

Levels per bay

Pallets per level

Units per pallet

Positions lost to honeycombing

Units you need to store

Usable unit capacity

121,651

506 usable pallet positions

Nominal positions576

Lost to honeycombing69

Positions needed175

Utilisation34.5%

Honeycombing is the empty space left when a partly-emptied pallet position cannot take another SKU. It typically costs 10% to 20% of nominal capacity, and it is the main reason a warehouse fills up before the pallet count says it should.

How the Rack Capacity Calculator works

Honeycombing is the empty space left when a partly-emptied position cannot take another SKU. It typically costs 10% to 20% of nominal capacity and it is the main reason a warehouse fills up before the pallet count says it should.

Also known as: pallet racking capacity · how many pallets per rack · racking layout calculator

Counting positions correctly

Rack capacity is bays times levels times pallets per bay, and each term has a catch. Bays are determined by the run length divided by bay width plus the upright thickness, which is why a 20 metre run does not give you exactly the number of bays the arithmetic first suggests.

Levels depend on clear height divided by the height needed per level, which is pallet height plus load height plus the clearance to lift in and out, usually 100 to 150mm. Add the beam depth. Getting five levels instead of four out of the same height is a 25% capacity gain and hinges on whether the load heights were measured or assumed.

Pallets per bay is normally two or three depending on beam length and pallet orientation. A 2.7 metre beam takes three UK pallets stored 1000mm face-on, or two stored 1200mm face-on, and the choice affects both capacity and how easily the pallets are reached.

Rack type, and the trade between density and access

Adjustable pallet racking gives access to every pallet and stores the fewest pallets per square metre, because every bay needs an aisle. It is the default for a reason: with a mixed catalogue and unpredictable picking, selectivity is worth more than density.

Drive-in racking removes aisles by letting the truck enter the rack, which raises density considerably and makes access last-in-first-out. It suits large quantities of few SKUs and is close to unusable for a broad catalogue.

Push-back and pallet flow sit between, offering first-in-first-out with better density than selective racking at a higher capital cost. The right choice follows from the catalogue shape rather than from the density figure, and operations that buy on density alone find themselves double-handling constantly.

The clearances that are not optional

Sprinkler heads need clearance beneath them, typically 500mm, and racking stacked into that clearance is both a fire risk and an insurance problem. The top beam level has to be set from the sprinklers rather than from the roof.

Aisle width follows the equipment, and the numbers are unforgiving. A counterbalance forklift needs roughly 3.2 to 3.5 metres. A reach truck manages 2.5 to 2.8. A very narrow aisle truck works in 1.6 to 1.8 metres but requires wire or rail guidance and a floor flat enough to specification. Each step down in aisle width buys real capacity and costs equipment flexibility.

Floor loading is the constraint nobody checks until it fails. Racking concentrates load on baseplates, and older floors or upper storeys may not take it. A structural check before installation costs a few hundred pounds and is considerably cheaper than remedial work afterwards.

Filling it, which is a different number

Rack capacity is theoretical. Utilisation is what you achieve, and a well-run warehouse runs at 85% to 90% of positions occupied rather than 100%, because you need free positions to receive, to reslot and to handle overflow.

Planning to 100% guarantees congestion. Goods arrive with nowhere to put them, get staged on the floor, block aisles, and the operation slows across the board. The last 10% of positions is not capacity, it is the working space that makes the other 90% usable.

Honeycombing is the other loss and it is less visible. A bay holding one pallet of a three-pallet slot is 67% empty and still counted as occupied. Measuring positions occupied overstates utilisation; measuring cube occupied against cube available shows the honeycombing, and in operations with many small SKUs the gap between the two figures is startling.

Slotting, which is where the capacity is won

Where a SKU sits matters as much as how many positions there are. Fast movers belong at floor and second level in the aisles nearest dispatch, because that is where pick time is lowest. Slow movers go high, far, and dense.

The usual rule is that a small share of SKUs generates most of the picks, and slotting those into the golden zone cuts pick times substantially without touching the rack layout. Operations that never reslot end up with their fastest lines wherever they happened to be put when they were new.

Reslotting is disruptive and worth doing periodically rather than continuously. Quarterly is common. The trigger is a change in the pick profile: a new bestseller, a seasonal shift, or a range change. Doing it from data rather than from memory is what separates a genuine improvement from moving boxes around.

Where to go next

The Rack Capacity question rarely arrives on its own. These are the ones that usually come with it:

Warehouse Utilization Calculator — A full warehouse is a slow warehouse.
Warehouse Space Calculator — Aisles and support space take most of it.
Bin Utilization Calculator — Bins sized for the largest SKU sit half empty.
Etsy Fee Calculator — Every Etsy fee on one sale, itemised.

Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price, check the platform's current fee schedule before you price a product against it. This is not tax or business advice.

Frequently asked questions

What is honeycombing?

Wasted space in a rack position that is partly empty but cannot be shared with another SKU. It is inherent to single-SKU-per-location storage and increases as pallets are picked down.

How much capacity does it cost?

Commonly 10% to 20% of nominal positions, higher with deep-lane or drive-in racking where whole lanes are dedicated to one SKU.

How do I reduce it?

Mixed-SKU pallets in reserve, dynamic slotting that consolidates part-pallets, and smaller pick faces replenished more often. Each adds handling and saves space.

What utilisation should I plan for?

Around 85% of usable positions is the practical ceiling. Above that, putaway and picking slow down because there is nowhere to move things temporarily.