What palletizing and pallet load patterns are
Palletizing is stacking cases, bags or packages in layers on a pallet to form a unit load that is handled, stored and shipped in one move. The pallet load pattern defines how each layer is laid out and how many layers fit on the pallet.
Three results come from that design: pallet area and volume utilization, load stability, and the handling and freight cost per case. A weak pattern wastes space all the way from receiving to shipping, as the calculation below shows.
Visual map of palletizing
The map summarizes the pallet and case data, the two patterns compared, the layer calculation and volume utilization.
How to calculate pallet utilization
The calculation has four steps: cases per layer, area utilization, number of layers and cases per pallet.
Area utilization (%) = cases per layer × case footprint ÷ pallet area × 100
Layers = whole number of (max height − pallet height) ÷ case height
Cases per pallet = cases per layer × layers
The theoretical number of cases per layer is the ratio of the areas, but the real number depends on the layout: cases must fit whole within the pallet dimensions, ideally without overhang past the edges.
Worked example: a 400 × 300 × 250 mm case
Example data (fictional): a 1.20 × 1.00 m pallet that is 0.15 m high, a maximum load height of 1.50 m including the pallet (a limit chosen for the example, not a standard) and a 400 × 300 × 250 mm case weighing 8 kg.
- Pallet area: 1.20 × 1.00 = 1.20 m².
- Case footprint: 0.40 × 0.30 = 0.12 m². Theoretical: 1.20 ÷ 0.12 = 10 cases per layer.
| Pattern | Layer layout | Cases per layer | Area utilization |
|---|---|---|---|
| A: aligned | 400 mm along the length (1,200 ÷ 400 = 3) and 300 mm across (1,000 ÷ 300 = 3, 100 mm left over) | 3 × 3 = 9 | 9 × 0.12 ÷ 1.20 = 90% |
| B: two blocks | A 1,200 × 400 mm strip with 4 turned cases (300 mm along the length) and a 1,200 × 600 mm strip with 3 × 2 = 6 cases | 4 + 6 = 10 | 10 × 0.12 ÷ 1.20 = 100% |
Layers: (1.50 − 0.15) ÷ 0.25 = 5.4, so 5 layers, giving a 1.25 m load and 1.40 m total height. The leftover 0.10 m cannot take another layer.
| Result | Pattern A | Pattern B |
|---|---|---|
| Cases per pallet | 9 × 5 = 45 | 10 × 5 = 50 |
| Load weight | 45 × 8 = 360 kg | 50 × 8 = 400 kg |
| Case volume (0.03 m³ each) | 1.35 m³ | 1.50 m³ |
| Volume utilization (of 1.20 × 1.00 × 1.35 = 1.62 m³) | 83.3% | 92.6% |
| Pallets for 2,000 cases | 2,000 ÷ 45 = 44.4, so 45 | 2,000 ÷ 50 = 40 |
Switching from pattern A to B saves 5 pallets out of 45 (11%) on the same order, with no change to case or pallet. Always check the pallet load rating and case strength before adopting a pattern.
Stacking patterns and interlocking
Pattern B covers the whole area, but if every layer is identical the joints line up and the stack becomes unstable. Interlocking fixes this by rotating or mirroring alternate layers.
| Pattern | What it is | Stability | When to use |
|---|---|---|---|
| Column | All layers identical, case directly over case | Low; relies on wrap or strapping | Strong cases that carry weight vertically |
| Interlocked (brick) | Alternating layers with offset joints | Medium to high | General pattern for corrugated cases |
| Pinwheel | Cases rotated around a center, layer by layer | High | Near-square cases on square or rectangular pallets |
In practice, pick the pattern that gives the most cases per layer, then check that alternating layers is possible. In the example, mirroring layer B by 180 degrees on the next layer offsets the joints without losing cases.
Height, weight and case strength
The number of layers is not set by height alone. Four limits drive the design:
- Maximum height: ceiling, rack beam level, truck or container, and lift truck reach.
- Weight: rating of the pallet, the rack and the handling equipment.
- Compression: the bottom case carries all the weight above; corrugated cases lose strength with humidity and storage time.
- Overhang: cases hanging past the edges reduce package strength and risk damage in handling; prefer full coverage or a small gap.
Unitizing with stretch wrap, strapping or corner boards keeps the load together in transit, but it does not fix an unstable pattern.
Where palletizing affects the warehouse
- Slotting: pallet height sets the rack opening, a topic of picking and storage.
- Space: the pallet count feeds directly into warehouse sizing.
- Control: a WMS stores the standard quantity per pallet and avoids manual counts.
- Shelf life: mixed pallets complicate FEFO and FIFO; prefer one lot per pallet.
- Internal flow: a standard pallet simplifies the internal milk run and line feeding.
- Handling: manual loading of heavy cases calls for ergonomics; a layer that is too high forces overreaching.
Common mistakes
- Using only the area ratio and ignoring that cases must fit whole.
- Counting layers without subtracting the pallet height.
- Stacking without checking the compression strength of the packaging.
- Forgetting the rack and truck height limits and finding the problem at shipping.
- Reusing one pattern for different cases and pallets without recalculating.
- Mixing products and lots on one pallet, which hurts traceability and picking.
Frequently asked questions
What is palletizing?
It is arranging packages in layers on a pallet to form a unit load for handling, storage and transport.
How do I calculate how many cases fit on a pallet?
Define the layer layout, multiply by the number of layers and check weight and strength. In the example, 10 cases per layer × 5 layers = 50 cases.
What size is a standard pallet?
It depends on the market. The Brazilian PBR pallet is 1.20 × 1.00 m, the Euro pallet is 1.20 × 0.80 m and the common North American pallet is 48 × 40 in. Always confirm the dimensions you actually use.
What is interlocking for?
It offsets the joints between layers, which makes the stack more stable in handling and transport.
What is pallet utilization?
It is the ratio of the area or volume taken up by the cases to the area or volume available. In the example, 100% of the area and 92.6% of the volume.
Can cases overhang the pallet?
Avoid it. Overhang lowers package strength and raises the risk of damage.
Sources
- FRAZELLE, E. World-Class Warehousing and Material Handling. New York: McGraw-Hill, 2002.
- TOMPKINS, J. A. et al. Facilities Planning. Hoboken: Wiley.
- RUSHTON, A.; CROUCHER, P.; BAKER, P. The Handbook of Logistics and Distribution Management. London: Kogan Page.
Keep studying: trusted sources and links
- ILOS: Instituto de Logística e Supply Chain (in Portuguese)
- CSCMP: Council of Supply Chain Management Professionals
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About the author
Lean Manufacturing & Behavioral Management Specialist
Over 20 years in the automotive and metalworking industries (GM and Dana), Lean Manufacturing practitioner since 2006. SENAI instructor and mentor in Brazil’s Brasil Mais Produtivo program, delivering consulting, training and audits for 50+ companies, combining quality, productivity and people development.
