About this calculator
"How many cartons fit in one container?" comes up in almost every export quotation. The quick answer of dividing container volume by carton volume is nearly always too optimistic, because cartons cannot be cut: leftover space at the end, along the sides and above the stack is lost. A difference of a few dozen cartons is enough to throw off the unit price, the number of containers or a promise to the buyer.
This calculator builds the load layer by layer. For each layer it searches for the best floor pattern by turning cartons 90° in the horizontal plane, including mixed patterns (some lengthwise, some crosswise) and pinwheel patterns. By default cartons stay upright (this side up). If you allow any side down, it also tries layers of different heights and combines them to use the container height better. A layer limit (the carton's stacking strength) and the weight per carton are optional; when you enter a weight, the count is capped by the container payload.
The result is a planning estimate for a single carton size. It does not reserve space for dunnage, hand or forklift loading clearance, bulging cartons or weight distribution. Leave a few centimetres of slack and, for mixed sizes or heavy cargo, open the result in the 3D Planner.
Worked example
Cartons of 60 × 40 × 40 cm loaded into a 20' GP (inside 5,898 × 2,352 × 2,393 mm):
- Upright layer (60 × 40 base): a mixed pattern of 8 cartons in the first 1,000 mm + 4 modules of 1,200 mm × 11 cartons = 52 per layer (a plain grid split gives only 51)
- Layers: 2,393 ÷ 400 = 5 layers → 52 × 5 = 260 cartons (≈ 75% of the volume)
- Any side down: 4 layers 400 mm high (52) + 1 layer 600 mm high (40 × 40 base, 14 × 5 = 70) = 2,200 mm
- Total: 4 × 52 + 70 = 278 cartons (≈ 80% of the volume)
Letting cartons lie on their side adds 18 cartons, provided the contents can travel that way.
How to use it
Choose the container
Pick a 20' GP, 40' GP, 40' HC or another type. Inside dimensions and payload are filled in from the catalogue.
Enter the carton size
Fill in the outer length, width and height of the carton, weight per carton if known, and a layer limit if the carton cannot be stacked high.
Set the orientation
Keep "upright" for cartons marked this side up, or allow any side down to try a denser arrangement.
Read the result and plan
See cartons per layer, number of layers, total cartons, volume used and whether space or weight is the limit, then open it in the 3D Planner.