A 40ft dry container (40GP, ISO code 42G1) measures about 12,032 × 2,352 × 2,393 mm inside, holds 67.7 m³ and has a typical payload of 26,730 kg. Width, height and door are identical to the 20ft box; only the length changes. The figure that surprises most first-time shippers: a 40GP carries less weight than a 20GP. This guide shows when a 40GP is the cheapest option and when it becomes a liability.
40ft container dimensions
The values below are typical. Manufacturers and owners differ by a few millimetres or a few hundred kilograms, so always check the door markings and the CSC plate.
| Parameter | Typical 40GP value |
|---|---|
| Inside length × width × height | 12,032 × 2,352 × 2,393 mm |
| Door opening (W × H) | 2,340 × 2,280 mm |
| Outside dimensions | 12,192 × 2,438 × 2,591 mm (40' × 8' × 8'6") |
| Floor area | 28.30 m² |
| Internal volume | 67.7 m³ |
| Tare | 3,750 kg |
| Maximum gross mass | 30,480 kg |
| Maximum payload | 26,730 kg |
| ISO size-type code | 42G1 |
For vessel and terminal capacity, a 40ft box counts as 2 TEU or 1 FEU. To see every type at once, use Container Sizes.
One 40GP or two 20GPs?
Physically a 40GP is close to two 20GPs joined end to end, but the numbers are not identical.
| Comparison | 1 × 40GP | 2 × 20GP |
|---|---|---|
| Internal volume | 67.7 m³ | 66.4 m³ |
| Floor area | 28.30 m² | 27.74 m² |
| 1200 × 1000 pallets, one layer (theoretical) | 22 | 18 |
| EUR pallets, one layer (theoretical) | 25 | 22 |
| Total payload | 26,730 kg | 56,500 kg |
| Total tare | 3,750 kg | 4,460 kg |
The pattern is clear. For light, bulky cargo the 40GP wins: more pallet positions (there is no second pair of end walls and doors eating floor space), one set of documents, one seal, one truck move and usually a lower ocean rate per cubic metre. For dense cargo two 20GPs win easily, because together they can carry more than twice the weight.
The density threshold
The quickest way to decide is to work out the cargo density in kg per m³. A payload of 26,730 kg divided by 67.7 m³ of internal volume gives about 395 kg/m³. If you can realistically fill only 85% (about 57.5 m³), the threshold rises to about 465 kg/m³. Anything denser reaches the weight limit before the box is full. This is the idea behind the stowage factor, and you can check it with the Stowage Factor Calculator.
On land the threshold is lower still. With the catalogue default of 26,000 kg container gross mass for a 40' trailer, the cargo you can carry is about 26,000 − 3,750 = 22,250 kg, or roughly 387 kg/m³ at an 85% fill. Use the figure in your trailer's KIR book, not the catalogue default.
Cargo that suits a 40GP
Based on the density threshold above, a 40GP is usually the right box for:
- Consumer goods in cartons: garments, footwear, toys, housewares and snacks, which rarely exceed 300 kg/m³.
- Furniture and handicrafts: rattan, processed wood and flat-pack furniture, light but bulky. If the packages come close to the door height, consider a 40HC.
- Single-layer pallets of moderate weight: for example 20 pallets of 1200 × 1000 mm at 800 kg each, 16,000 kg in total, comfortable for the box, the truck and the ship.
- Long items: pipes, aluminium profiles or boards longer than 5.8 m that will not fit a 20ft, provided they can pass through the door and be properly secured.
A 40GP is a poor fit for cement, tiles, stone, metals, paper reels or dense liquids in drums. Those loads reach the weight limit when the floor is barely half used, and the empty space becomes money you paid for and did not use.
Practical points at the warehouse and depot
Make sure your loading area can take a 40ft trailer: the combination is far longer than a rigid truck and needs manoeuvring room and access roads of a suitable class. Ask the depot whether the unit is really a 40GP; at some locations high cubes are more common and carriers may substitute them. If you receive a 40HC instead, re-check the payload and door height before stuffing.
The weight-out risk
An overweight 40ft box sets off a chain of problems: the truck fails at the weighbridge, the terminal refuses the box because the VGM exceeds the maximum gross mass, or part of the cargo has to be unloaded. Re-handling, storage and delays almost always cost more than the difference in freight for two 20GPs.
Beyond total weight, watch the distribution. A 40ft floor is long; heavy cargo bunched at one end shifts the centre of gravity and overloads one side of the chassis. A widely used carrier guideline keeps the cargo centre of gravity within about ±5% of the inner length from the midpoint, around ±0.6 m for a 40ft container. More on this in our guide to centre of gravity and weight distribution.
Worked example
Case 1 — light cartons. A garment factory ships 600 × 400 × 400 mm cartons at 30 kg each. In one orientation: 12,032 / 600 = 20, 2,352 / 400 = 5, 2,393 / 400 = 5, so 20 × 5 × 5 = 500 cartons.
- Volume: 500 × 0.096 m³ = 48 m³ (about 71% of internal volume).
- Weight: 500 × 30 kg = 15,000 kg; container gross mass 18,750 kg.
- Conclusion: a 40GP is ideal. Two 20GPs hold only 2 × 225 = 450 cartons in the same arrangement, and usually cost more.
Case 2 — dense ceramic tiles. A distributor ships 18 pallets of 1200 × 1000 mm at 1,300 kg each.
- In a 40GP: 18 × 1,300 = 23,400 kg of cargo, gross mass 23,400 + 3,750 = 27,150 kg. That is within the container's payload and maximum gross mass, but above the 26,000 kg trailer default.
- In 2 × 20GP: 9 pallets each, 11,700 kg of cargo and 13,930 kg gross per container. Fine for both truck and ship.
- Conclusion: even though the pallets fit in the 40ft space, this load belongs in two 20GPs.
The underlying volume maths is in how to calculate CBM, and pallet patterns are explained in how many pallets fit in a container.
Common mistakes
- Assuming a 40ft carries twice the weight of a 20ft. A 40GP payload is about 26,730 kg, not 56,500 kg.
- Ignoring truck limits. Check the truck and trailer combination in Indonesian truck sizes and with the ODOL Check.
- Booking a 40GP for tall cargo. If double-stacked pallets reach more than about 2.3 m, you need a 40ft high cube.
- Concentrating weight at one end. Spread heavy items along the floor, use dunnage and secure the load against shifting.
- Leaving the door area open. The gap at the door must be filled or braced so cargo cannot fall out when the doors are opened.
Next steps
Compare all three sizes side by side in 20ft vs 40ft vs 40HC or in Container Compare. Then load your packing list into the 3D load planner to see the arrangement, free space and estimated weight. Planner output is a simulation; official weighing, the VGM and the carrier's or terminal's acceptance remain the reference.