Summary
Palletization is the process of stacking goods on a pallet and securing them so they move as one unit load. Palletized goods are goods that already sit on a pallet, and to palletize is to put them there. A sound pallet keeps the heaviest cases at the bottom, stays inside the pallet edges and follows each item's handling rules. Single-SKU pallets are easy to plan. Mixed pallets built from customer orders are where warehouses lose time, truck space and stability.
On a warehouse floor, palletization is a job that repeats hundreds of times a shift. Someone decides which case goes down first, which goes on top and when a pallet is full. Those small decisions set how many pallets leave the dock, how much truck space you book and how many cases arrive crushed.
For a pallet of one product, the decisions are made once and repeated for every pallet. For a store order with dozens of SKUs, they are made again for every order, usually by the person building the pallet while they pick. The mixed pallet is where the cost sits, and it is also where a plan helps most.
What does palletized mean?
Palletized describes goods that sit on a pallet and are secured as one load, usually with stretch wrap or straps. Palletized freight, a palletized shipment and palletized cargo all travel this way. The alternative is floor loading: loose cartons stacked by hand on the trailer floor and unloaded the same way.
The word comes in a few forms. To palletize is the verb: you palletize boxes. Palletizing and palletization name the same process, and palletized is the result. British English spells them with an s: palletise, palletising, palletisation. Depalletizing is the reverse, taking a pallet load apart at receiving or at the start of a production line.
All of it comes back to the unit load. iGPS, a pallet pooling company, puts it this way: palletizing involves converting multiple smaller products into a single load that can be moved as one unit. One forklift or pallet jack trip replaces dozens of hand moves, and racking, dock doors and trailers are all sized around that one load.
The pallet itself is close to standard in each region. The FedEx Freight pallet packing guide notes that standard wood pallets typically measure 40 x 48 inches, the common North American size. In Europe the EPAL Euro pallet is 1,200 x 800 mm and 144 mm high, weighs about 25 kg and has a safe working load of 1,500 kg. Those figures set the footprint you build on and the weight you can put on it.
Advantages and disadvantages of palletization
Palletization trades some space and weight for faster, safer handling. For most freight that moves through a warehouse the trade pays off. The costs are real, though, and they grow quickly when pallets are built badly.
Advantages
The first gain is handling. A pallet moves in one forklift or pallet jack trip, where loose cartons need a person to lift each one at every transfer: from the pick location to staging, from staging into the trailer, and again at the receiving end. Fewer touches mean faster loading and fewer chances to drop something.
The second is protection. Wrapped cases support each other and cannot slide apart in transit. People also stop carrying cases by hand at the dock, which takes repetitive lifting out of the job.
The third is fit with the rest of the building. Pallet racking, dock doors and trailers are built around pallet footprints, so a palletized load drops into slots the warehouse already has. It also counts as one unit: one label, one scan, one line on the bill of lading.
Disadvantages
The pallet takes space and payload of its own. An EUR pallet adds 144 mm of height and about 25 kg before the first case goes on, and on a trailer that fills up by height or by weight, you pay for that space. Pallets and stretch wrap also cost money, and pallets have to be bought, exchanged or returned.
A half-full pallet ships air. A partial pallet still takes a full floor position on the truck, and an order split across more pallets than it needs repeats that cost on every shipment.
A badly built pallet can be worse than loose cases. Overhang, a heavy case on top of a fragile one or an uneven top layer can bring the load down in a rack or in a trailer. For mixed pallets, build quality varies from one pallet to the next, because each one is planned on the spot.
Types of palletization: single-SKU and mixed pallets
There are two types of pallet load, and they behave very differently. A single-SKU pallet holds one product, with every case the same size and weight. A mixed pallet, also called a mixed-case or rainbow pallet, holds several products for one destination, such as a store, a wholesaler or a large B2B customer.
Single-SKU pallets usually come from a production line or a supplier. The stacking pattern is worked out once for each case size and then repeated, often by a conventional palletizer at the end of the line. The plan does not change from pallet to pallet, so a stable build is easy to repeat.
Mixed pallets are built in the warehouse from customer orders, usually by people who pick cases from their locations and stack them as they go. Every order is a new 3D packing problem, with different case sizes, weights, crush strengths and handling rules, and the plan has to be made while the order is picked.
Both types can be built by hand, by a person following instructions from software, or by a robot cell. In the warehouses we work with, mixed pallets are mostly built by hand. A robot cell for mixed cases is a large capital project, and it gets harder to run as the product mix changes. The four set-ups and when each one fits are compared in our guide to mixed palletization types and when to automate.
How to palletize boxes in 7 steps
The same seven steps apply whether you build one pallet a day or three hundred. They follow from two physical facts: a carton carries weight through its walls and corners, and any part of a case that hangs over the edge has nothing underneath it.
1. Start with a sound pallet of the right size
Check the pallet for broken boards and protruding nails before anything goes on it. Match the footprint to where the load is going: a 48 x 40 inch pallet for most North American freight, an EUR pallet for European retail and distribution. Note the safe working load, 1,500 kg for an EPAL Euro pallet, and the height limit your customer, carrier or racking sets.
2. Heavy and strong at the bottom, fragile on top
Put the heaviest, strongest cases on the bottom layer and build lighter, weaker cases on top. Cases marked do not stack go on the top layer. Keep this-side-up arrows pointing up, and keep goods that may not travel together apart: chemicals, flammables or chilled items often cannot share a pallet with food or general goods.
3. Keep every case inside the pallet edges
Overhang can undo an otherwise well-stacked pallet. A case that hangs over the edge loses the support under its walls, and the same FedEx Freight guide warns that overhang can reduce package compression strength by as much as 32 percent. A 2024 report by Virginia Tech for the Fibre Box Association cites the Fibre Box Handbook, which estimates the reduction at between 20% and 40% of the original strength. Build to the edge and no further.
4. Choose column or interlocked stacking
Column stacking puts each case directly on top of the one below, corner on corner, so the weight runs straight down the strongest part of the carton. FedEx Freight states that in almost all cases, column stacking increases the top-to-bottom compression strength of palletized shipments. Interlocked stacking, also called brick or cross stacking, turns each layer so that cases bridge the joints of the layer below. According to the same guide, interlocking cartons can increase stability if the carton contents are rigid.
The choice depends on the product. Weak cartons with soft contents need the strength of columns, while rigid cases that could shift in transit gain more from interlocking layers. Mixed pallets often add cases of different heights to the same load, which then have to fit together across the stack and on top. The illustrations below show all three patterns: layer mode, tower mode and multi-height items.
5. Stay under the height and weight limits
Height limits come from three places: the customer's receiving rules, the trailer and the racking the pallet will sit in. Weight limits come from the pallet's safe working load and from the carrier. Check both before you start a new layer, because taking a layer off a wrapped pallet is slow work.
6. Fill gaps and keep the top flat
Gaps let cases slide when the truck brakes or turns. Fill voids with cases that fit or with dunnage, and keep the top layer as flat as you can, so a top sheet or a second pallet rests on it evenly.
7. Wrap, label and measure
Wrap from the base of the pallet upwards, so the film ties the load to the pallet as well as the cases to each other. Record the real dimensions and weight once the pallet is wrapped, because those are the figures the carrier will check. Our guide on how to measure a pallet covers the steps.
Why mixed palletization is hard in a warehouse
The seven steps are simple for one pallet and a person with time to think. A picker building mixed pallets applies them hundreds of times a shift, while walking, lifting and scanning, and the order decides which cases arrive in which sequence.
Without a plan, the next case goes wherever there is room. The build then depends on how long the person has done this job. Someone with years on the floor knows that the bottled water goes down first and the crisps go last. Someone in their first week of peak season has not had the chance to learn that yet, and nothing on the scanner tells them.
Pick-to-pallet adds a second problem. The shortest pick route and the best stacking order rarely match: the heavy case may sit at the far end of the aisle and the fragile one near the start. Optimize the route and the build suffers; optimize the build and the walk grows. The target is the shortest route that still gives a stable pallet. Our article on mixed palletizing in pick and pack operations goes into that trade-off, and the guide to case picking shows how the pick sequence decides how stable the pallet is.
The WMS rarely helps here. It assigns orders, locations and pick confirmations, but it does not plan where each case goes on the pallet, in what sequence, or within which weight, height and handling rules.
The cost shows up downstream. If nobody knows how many pallets an order needs until it is built, the staging lane overflows, the carrier is booked for the wrong number of pallets, and the extra pallet turns into a surprise freight charge. Unstable pallets come back later as damage claims.
What system-guided palletization changes
System-guided palletization moves the stacking decision from the person on the floor to a plan. Software calculates the pallet build for each order before picking starts, from item dimensions, weights and handling rules, and shows the result to the person doing the work.
Pulse, the Optioryx warehouse optimization software, does this on top of the WMS or ERP you already run, or as a standalone web app without integration. It calculates the pallet count and configuration when the sales order is created, so your customer gets the right shipping cost and you can book the right truck capacity before anything is picked.
On the floor, Pulse shows the operator where every case goes in a 2D step-by-step view. In a pick-to-pallet flow, the pick sequence follows the stacking order from the bottom up, so the heavy cases come first and the buffer step between picking and pallet building disappears. The stacking pattern is set per item profile: flat interlocking layers, towers, or cases of different heights in one layer. The video shows the operator screen, with a top view of the pallet and numbered case positions.
Weight limits, maximum height, orientation and do-not-stack rules are part of the plan, and goods that must travel apart, such as chemicals, flammables or chilled items, are split across pallets. When stock falls short, the plan is recalculated, so the operator is not left to solve a gap on the spot.
Across customer deployments, Pulse lowers transport cost by 10 to 30%, and operations that combine picking with pallet stacking need around 10% fewer pickers.
The plan relies on accurate case dimensions and weights, and seven other warehouse processes depend on the same item dimensions. Underneath the plan sits a 3D packing problem, explained in our article on 3D bin packing.
To size the gain for your own operation, the palletization ROI calculator takes your pallet-building headcount, yearly pallet volume and damage cost. The 3D palletization product sheet sums up the setup on one page, and our palletization software comparison sets Pulse next to the other tools on the market.
Questions?
Palletized means placed on a pallet and secured as one load, usually with stretch wrap or straps. Palletized freight or a palletized shipment travels on pallets and is moved by forklift or pallet jack. The alternative is floor loading, where loose cases are stacked by hand on the trailer floor.
Both spellings are correct. Palletize, palletizing and palletization are American English; palletise, palletising and palletisation are British English. All of them describe the same process: stacking goods on a pallet so they move as one unit load.
Palletizing builds a pallet load by stacking cases onto a pallet. Depalletizing is the reverse: taking the cases off a pallet, for example at receiving or at the start of a production line. Both can be done by hand or by machine.
A mixed pallet holds several different products, or SKUs, for one destination such as a store or a B2B customer. It is built in the warehouse from a customer order, so the stacking plan changes with every order. Heavy, strong cases go at the bottom and fragile ones on top to keep it stable.
Palletization software calculates how to stack a set of cases on one or more pallets within weight, height and handling rules. Tools such as Pulse by Optioryx also give the pallet count when the order is created and show operators where each case goes, step by step, while they build the pallet.