Pallet loading guide

The short version

A pallet calculation has three separate limits: footprint, height and weight. The footprint determines how many cartons fit on one layer. The available stack height determines how many complete layers can be added. Payload then caps the total if the cartons are heavy. A useful calculator must evaluate all three rather than divide pallet volume by carton volume.

1. Start with the box footprint

Suppose a pallet measures 1200 × 800 mm and a carton measures 400 × 300 × 250 mm. If the carton stands with the 400 × 300 mm face on the pallet, a simple aligned grid fits three cartons along the 1200 mm side and two along the 800 mm side: 3 × 2 = 6 cartons per layer.

Rotate the footprint by 90°. Now the 300 mm side runs along the pallet length and the 400 mm side runs across the width. Four cartons fit along 1200 mm and two fit along 800 mm: 4 × 2 = 8 cartons per layer. That single rotation increases the simple-grid capacity from six to eight without changing pallet area or carton volume.

2. Test more than one layer pattern

Aligned rows are only the first candidate. Some dimensions leave a strip that cannot take another carton in the same orientation but can accept a rotated carton. That is why PackMize tests aligned, rotated and mixed rectangular placements. PackMize uses multiple deterministic strategies and reports PROVEN OPTIMAL only when the layer and final capacity reach valid mathematical bounds; otherwise it reports BEST SOLUTION FOUND.

For planning purposes, the important output from this stage is TI: the number of cartons on one layer. The layout should also show how much of the pallet surface is occupied so that a high count is not confused with perfect coverage.

3. Convert TI into HI

HI is the number of vertical layers. It depends on the maximum permitted total pallet height, the pallet base height and the vertical carton dimension used by the chosen orientation.

Using the same 250 mm carton height, assume a 144 mm pallet base and a 1500 mm maximum total height. The usable stack height is:

1500 − 144 = 1356 mm

Five complete 250 mm layers use 1250 mm. Six would require 1500 mm of cartons before even adding the pallet base, so only five layers are feasible. If TI is eight, the geometric height capacity is therefore 8 × 5 = 40 cartons.

4. Apply payload and quantity limits

Geometry is not always the final constraint. If each carton weighs 40 kg, forty cartons would weigh 1600 kg before adding pallet tare. A pallet configured for a 1500 kg maximum load cannot carry that many. The calculator must cap the count by weight and then by the quantity actually available.

5. Read utilization correctly

Surface utilization compares the area occupied by cartons on one layer with the pallet footprint. Volume utilization compares the volume of fitted cartons with the rectangular volume envelope available above the pallet. Both are useful planning metrics, but neither says that the load is stable or transport-safe. A 95% geometric utilization can still be unacceptable if the cartons are fragile, overhang is prohibited, the center of gravity is poor or the stack requires interlocking for stability.

What PackMize does and does not model

The Pallet Calculator models rigid rectangular boxes on a rectangular pallet, valid 90-degree footprint orientations, mixed layer placement, stack height, pallet tare, maximum load and requested quantity. It does not model carton deformation, crush strength, friction, straps, stretch wrap, load stability, overhang rules, center of gravity or carrier-specific regulations.

That distinction matters. PackMize is a planning optimizer, not a pallet engineering certification tool.

Practical workflow

1. Use the real external carton dimensions, not nominal product dimensions.
2. Select the actual pallet standard or enter a custom footprint.
3. Disable rotations that are physically prohibited by the product.
4. Enter the real maximum stack height and payload.
5. Run the optimizer and inspect both the count and the layer diagram.
6. Validate stability and handling constraints outside the generic calculator before operational use.

Assumptions and data sources

The worked Euro-pallet dimensions can be checked against the EPAL Euro pallet datasheet. ISO 6780:2003 provides broader dimensional standards context. For other pallet systems, use the actual supplier or pool specification.

Frequently asked questions

Specification reference: EPAL Euro pallet specifications list the 800 × 1200 mm footprint, 144 mm height, approximate 25 kg tare and 1500 kg safe working load. Always check the pallet condition and the actual load constraints.