Container load.

How cartons per container are calculated

The container floor (inside length × inside width) is treated as one big pallet and the inside height as the stacking limit. For each allowed carton orientation (three if you do not need “this side up”, one otherwise) the tool compares uniform grids and two-block row layouts, keeps the layer with the most cartons, then stacks floor(inside height ÷ carton height) layers. That is the volume (space) limit. The weight limit is floor(max payload ÷ carton weight). Cartons per container = the smaller of the two; the tool names which one governs. CBM utilisation = cartons × carton volume ÷ stated cubic capacity. Containers needed = order quantity ÷ cartons per container, rounded up.

Worked example

A 400 × 300 × 250 mm carton at 8 kg in a 40 ft high cube (12,032 × 2,350 × 2,695 mm inside, 28,800 kg payload): the best floor layer holds 230 cartons and 10 layers fit (2,695 ÷ 250), so the volume limit is 2,300 cartons; the weight limit is 28,800 ÷ 8 = 3,600 cartons. Volume governs: 2,300 cartons, about 90.6% of the 76.2 m³ stated capacity, 18,400 kg of cargo. A 30 kg carton of the same size flips the limit: 960 cartons by weight, only 37.8% of the cube.

What this model does not solve

Axis-aligned rectangular cartons only: no pinwheel or interlocking patterns beyond two blocks, no pallets, dunnage, load bars, air gaps, door-end clearance, container floor-loading or axle/road weight limits, and no mixed cartons. Real loads are usually a little lower than the geometric best case. The check that a carton fits through the door opening is a size test only. Confirm every booking with your forwarder or carrier.

Sources and as-of date

Inside length, width, height, door opening, cubic capacity, tare and payload for the 20 ft, 40 ft and 40 ft high cube dry containers come from ONE’s Container Information page (one-line.com, Dry Containers, read 2026-10-01): 20 ft 5,898 × 2,350 × 2,390 mm, 33.1 m³, 28,330 kg payload; 40 ft 12,032 × 2,350 × 2,390 mm, 67.6 m³, 26,840 kg; 40 ft HC 12,032 × 2,350 × 2,695 mm, 76.2 m³, 28,800 kg. Doors are 2,340 mm wide and 2,280 mm (20/40) or 2,585 mm (HC) high. Individual carriers and container builds vary; always use the specification on your own booking.

FAQ

Why is my CBM utilisation never 100%?

Cartons are rectangles on a fixed floor, so leftover strips and the gap above the top layer are unused, and stated capacity is slightly larger than a simple stack can reach.

Weight limit or volume limit: which matters?

Light, bulky goods hit the volume limit first; dense goods such as tiles or liquids in cartons hit the payload first. The result tells you which one governs.

Does this include pallets?

No. It models floor-loaded (loose) cartons. For palletised freight, plan the pallet with the Ti-Hi calculator and allow for pallet height and weight.