Before booking a container, exporters need to know how many cartons will fit. Too few and you pay for empty space; too many and the extra cartons are left behind. The answer depends on container size, carton dimensions, orientation and weight. This guide shows the calculation, using our free Container Loading Calculator.
Container internal dimensions (typical)
| Container | Length | Width | Height | Volume |
|---|---|---|---|---|
| 20 ft standard | 5.90 m | 2.35 m | 2.39 m | about 33 CBM |
| 40 ft standard | 12.03 m | 2.35 m | 2.39 m | about 67 CBM |
| 40 ft high cube | 12.03 m | 2.35 m | 2.69 m | about 76 CBM |
Exact sizes vary slightly by manufacturer.
The method
For each orientation:
Cartons = floor(Container L ÷ carton l) × floor(Container W ÷ carton w) × floor(Container H ÷ carton h)
Test all six orientations, and allow a few centimetres for loading gaps.
Worked example: 20 ft container
Carton: 60 × 40 × 35 cm.
| Orientation (along L, W, H) | Count |
|---|---|
| 60, 40, 35 | 9 × 5 × 6 = 270 |
| 40, 60, 35 | 14 × 3 × 6 = 252 |
| 35, 40, 60 | 16 × 5 × 3 = 240 |
Best: 270 cartons, using 270 × 0.084 = 22.7 CBM of 33 CBM (about 68%). Mixing orientations to fill leftover gaps can increase this.
Weight limits
Containers also have a maximum payload, often around 25 to 28 tonnes, but road weight limits in the origin or destination country may be lower. If 270 cartons weigh 25 kg each, the load is 6,750 kg, well within limits.
Practical usable volume
Loaders rarely achieve 100% fill. Realistic carton loads are about 25 to 28 CBM in a 20 ft and 55 to 60 CBM in a 40 ft.
Palletised loads
Pallets reduce capacity but speed handling. See the Pallet Capacity Calculator.
For loading tips, read container loading tips. Calculate carton CBM with the CBM Calculator.
Frequently asked questions
How many CBM does a 20 ft container hold?
About 33 CBM internally; around 25 to 28 CBM is realistic for cartons.
How many CBM in a 40 ft high cube?
About 76 CBM internally.
Should I test different carton orientations?
Yes, orientation can change the count significantly.