There is no fixed carton count for a 20ft or 40ft container. The answer depends on each packed carton’s dimensions, allowed orientation, weight and stacking limit. Calculate volume and payload upper bounds first, then check a whole-carton arrangement inside the usable dimensions.
What information do you need before calculating?
Record packed length, width, height and gross weight, plus the permitted rotations. Specify any maximum layer count or stack height. Confirm the container’s internal dimensions and payload, then reserve space for the roof, door end and materials that the arrangement must not occupy.
Use a single cargo type in capacity mode to estimate a feasible quantity. For an existing order, enter the requested quantity in order mode. A capacity estimate and an order fulfilment result are different questions.
Start with a simple, reproducible grid
Use the site’s 20GP preset: 589 × 235 × 239 cm, with 10 cm reserved at the door end and 5 cm below the roof. For 60 × 40 × 30 cm cartons fixed with the 30 cm dimension upright, the usable grid is 579 × 235 × 234 cm.
Rounding down on each axis gives nine positions along the length, five across the width and seven layers: 315 cartons. At 15 kg each the load weighs 4,725 kg. The carton volume is 22.68 m³, approximately 68.56% of the preset’s full internal volume.
floor(579 ÷ 60) × floor(235 ÷ 40) × floor(234 ÷ 30) = 9 × 5 × 7 = 315
Compare the grid with the upper bounds
The preset’s full internal volume is approximately 33.081185 m³. Dividing by 0.072 m³ per carton gives a loose volume upper bound of 459 cartons before clearance. Dividing the 28,200 kg payload setting by 15 kg gives a weight upper bound of 1,880 cartons. Neither bound proves that its count can be arranged.
In this example, geometry is the more restrictive issue. A narrower carton, a different permitted orientation or a different floor partition could use a strip that the simple grid leaves empty. Only a layout check can tell which proposed change actually helps.
| Check | Count | Meaning |
|---|---|---|
| Volume only | 459 | Loose upper bound; ignores geometry and clearance |
| Payload only | 1,880 | Upper bound for the stated gross weight |
| Fixed grid | 315 | Illustrative arrangement under the stated rules |
What does the planner add, and what remains outside it?
The planner searches floor partitions and vertical stacks of the same cargo type, then independently checks bounds, overlap, quantities, orientation, stacking rules and total weight. It can find arrangements beyond a single uniform grid, but it does not prove the global maximum.
It does not mix different SKUs vertically or calculate package compression, securing, axle loads or loading-path feasibility. The animation shows placement coordinates, not an approved physical sequence. Check the actual doorway and handling method, and review the result against packing guidance before using it on the floor.
- Change one assumption at a time when comparing layouts.
- Keep carton orientation consistent with handling labels.
- Review unplaced units, not only the utilization percentage.
- Export the input rules with the final layout.
Open the load planner
Use your actual carton dimensions, weight and stacking rules to turn this example into a checked layout.
Start planningFAQ
Why does the calculator show fewer boxes than a CBM calculation?
CBM division ignores whole-box geometry, clearance, weight and stacking restrictions. A lower checked quantity can be more useful than a larger volume-only upper bound.
Is a high utilization percentage always a better load?
No. It does not establish stability, package strength, access or securing. Compare the loaded order and operational constraints as well as volume usage.