Containers are standardised by ISO, but "a container" can mean several very different boxes. Choosing the right type and size affects your freight cost, how much you can load and whether your cargo arrives undamaged.
Dry containers: the standard boxes
Typical values — exact figures vary slightly by manufacturer and owner, so always check with the carrier.
| 20’ Dry | 40’ Dry | 40’ High Cube | |
|---|---|---|---|
| Internal length | 5.90 m | 12.03 m | 12.03 m |
| Internal width | 2.35 m | 2.35 m | 2.35 m |
| Internal height | 2.39 m | 2.39 m | 2.69 m |
| Volume | ≈ 33 m³ | ≈ 67 m³ | ≈ 76 m³ |
| Max payload (approx.) | ≈ 28 t | ≈ 26–28 t | ≈ 26–28 t |
| Euro pallets (1.2 × 0.8 m), single level | 11 | 24–25 | 24–25 |
A practical point: the theoretical volume is never fully usable. Count on loading around 25–28 m³ in a 20’ and 55–60 m³ in a 40’, depending on the shape of your cargo.
20’ or 40’?
- 20’ for heavy, dense cargo (tiles, stone, metal, bagged goods): you reach the weight limit before the box is full.
- 40’ for lighter, bulky cargo (furniture, textiles, consumer goods). It does not cost twice a 20’, so the cost per m³ is lower.
- 40’ High Cube adds 30 cm in height — about 13% more volume — for light, voluminous goods.
Special containers
- Reefer (20’ or 40’): insulated, with its own refrigeration unit, maintaining a set temperature typically from about –30 °C to +30 °C. The insulation reduces the internal dimensions slightly. Used for perishables and pharmaceuticals.
- Open top: no rigid roof, covered by a tarpaulin, for cargo too tall for the doors or that must be loaded by crane from above (machinery, stone blocks).
- Flat rack: a base with end walls but no side walls or roof, for oversized or heavy cargo such as vehicles, boats or industrial equipment — often "out of gauge".
- Ventilated and insulated variants exist for specific products such as coffee or certain foodstuffs.
Weight rules: VGM
Since 2016, the SOLAS convention requires the shipper to provide the Verified Gross Mass (VGM) of every packed container before it is loaded on a ship. Without it, the container will not be loaded. Road weight limits in the countries of origin and destination can also be lower than the container’s maximum payload — check before loading heavy cargo.
Five loading tips
- Distribute weight evenly along the floor; avoid concentrating it at one end.
- Put heavy items at the bottom and secure the load against movement (lashing, airbags, bracing).
- Use moisture absorbers for long voyages to prevent "container rain".
- Check that wooden packaging and pallets comply with ISPM 15 (heat-treated and stamped).
- Photograph the loaded container before closing and note the seal number.
Need the right box?
We book all container types through Casablanca and Tanger Med, including reefers and special equipment. See our sea freight service or send us your cargo details and we will recommend the right container.
