About this calculator
The loading pattern decides how many cartons fit in one pallet layer and how stable and strong the stack is. There are two basic approaches. Column stacking places each carton exactly on top of the one below, corner on corner, so the full compression strength of the boxes is used. Interlocking (brick pattern) mixes carton orientations and turns the next layer so the cartons bind together; the stack is more stable when moved by forklift or shaken on a truck, but the load no longer sits squarely on the corners, so stacking strength goes down.
This calculator finds two patterns. The column pattern is the best uniform grid of the two carton orientations. The best pattern looks for the most cartons per layer, using staged straight cuts (guillotine) or a pinwheel: four blocks of cartons turning around a small hole in the middle. A pinwheel sometimes fits cartons that no straight-cut layout can reach. For mixed patterns, every even layer is turned 180° so the stack interlocks. The result shows the count per layer, area efficiency and a drawing of both layers.
Choose the pattern for the job. For heavy goods or long storage in a humid warehouse, column stacking with stretch film and corner boards is often safer; for light cartons that are handled a lot, interlocking helps stability. Check box strength with the box stacking calculator, and check the overhang rules of your buyer or destination warehouse.
Worked example
Cartons of 400 × 300 mm on a 1200 × 1000 mm pallet without overhang.
- Column pattern: 1,200 ÷ 400 = 3 and 1,000 ÷ 300 = 3 → 9 cartons per layer, efficiency 9 × 0.12 ÷ 1.2 = 90%
- Best pattern: 3 × 2 cartons in a 1,200 × 600 mm strip + 4 turned cartons (300 × 400) in a 1,200 × 400 mm strip → 10 cartons, 100% efficiency
- Even layers of the best pattern are turned 180° → an interlocked stack; the column pattern stays straight
- Pinwheel: in a 5 × 5 square, 3 × 2 boxes fit only 3 with straight cuts but 4 as a pinwheel
The best pattern fits one more carton per layer (11% more), at the cost of somewhat lower stacking strength than the column pattern.
How to use it
Choose the pallet
Pick a pallet size from the catalogue (such as 1200 × 1000 or Euro 1200 × 800) or enter your own, and set the allowed overhang.
Enter the carton size
Enter the outer length and width of the carton; height does not affect the pattern of a single layer.
Compare the patterns
See the best and the column pattern, cartons per layer, area efficiency and whether the stack interlocks.
Continue planning
Take the pattern to the cartons-per-pallet calculator or the 3D Planner to work out layers, weight and pallets per container.