345 cartons fit a 20ft container, and you will not load 345
A 60 × 40 × 40 cm carton is 0.096 m³. A 20ft dry container is about 33.2 m³ inside. Divide one by the other and 345 cartons fit.
No they don't. But the number is still worth having, as long as you know what kind of number it is.
| Container | Internal volume | Cartons by volume | 400 cartons fill | Containers needed |
|---|---|---|---|---|
| 20ft | 33.2 m³ | 345 | 115.66% | 2 |
| 40ft | 67.7 m³ | 705 | 56.72% | 1 |
| 40ft high-cube | 76.4 m³ | 795 | 50.26% | 1 |
Everything the division ignores
Cartons do not tessellate into a steel box. The division assumes your cargo is a liquid that takes the container's shape, and it isn't:
- Stacking geometry. 60 cm does not divide neatly into a container's internal length or width, and the remainder is dead air at one end.
- Pallets. If the goods are palletised, you are loading pallets, not cartons, and the pallet's own footprint and deck height come out of the cube before your cargo does.
- Weight. A container has a payload limit as well as a volume. Dense cargo hits the weight ceiling with the box half empty, and no amount of volume arithmetic will tell you that.
- Bracing and access. Dunnage, airbags and a door-end gap you can actually work in are all real and all volume.
A commonly used planning haircut is 80–85% of the geometric figure, which would put this load nearer 293 cartons a container than 345. That is a rule of thumb, not a measurement — your packer's actual stack plan beats it every time.
Where the ceiling earns its keep
The honest use of the number is as an upper bound for a decision you make before anyone stacks anything. Here, 400 cartons is 115.66% of a 20ft — so two 20ft containers, each running comparatively empty — against 56.72% of a single 40ft. That comparison survives the haircut, because the haircut applies to both sides. A ceiling is a bad loading plan and a perfectly good way to choose an equipment type.
Work it for your own shipment
The figures above come from the same code the calculators run, so typing these inputs in reproduces them exactly. Your own numbers are the point though — size your own cartons against each container in the container load calculator, and check the chargeable weight if you are shipping air rather than sea.
These are estimates, not assessments. Duty rates, the taxable base, and the valuation rules that decide them are set by national law and by how your goods are classified. A customs broker or your national customs authority gives you the binding answer; this site gives you the arithmetic so you know roughly what is coming and which question to ask.