The standard boxes
Figures below are typical for dry containers in general circulation. Individual boxes vary, and the numbers that legally matter — tare and maximum gross — are stamped on each container's CSC plate. Always read the box.
| Type | Internal L × W × H | Capacity | Tare | Max payload |
|---|---|---|---|---|
| 20ft general purpose | 5.90 × 2.35 × 2.39 m | ~33 m³ | ~2,250 kg | ~28,200 kg |
| 40ft general purpose | 12.03 × 2.35 × 2.39 m | ~67 m³ | ~3,750 kg | ~26,700 kg |
| 40ft high cube | 12.03 × 2.35 × 2.69 m | ~76 m³ | ~3,900 kg | ~26,580 kg |
| 20ft reefer | 5.45 × 2.29 × 2.27 m | ~28 m³ | ~3,000 kg | ~27,400 kg |
| 40ft high cube reefer | 11.58 × 2.29 × 2.50 m | ~67 m³ | ~4,800 kg | ~25,600 kg |
Maximum gross mass for most dry containers is 30,480 kg, which is where the payload figures above come from. Some 20ft boxes are plated for a higher gross. The reefer figures are smaller inside because the insulation and the machinery both take space.
Specialised equipment
- Open top — a 20ft or 40ft box with a removable tarpaulin roof, for cargo that has to be loaded by crane from above. Cargo protruding above the roof line is out of gauge and priced accordingly.
- Flat rack — a floor with fixed or collapsible end walls, for machinery and units too wide or too tall for a box. Lashing and securing become your responsibility to specify.
- Platform — floor only, for genuinely oversized single pieces.
- Tank — for bulk liquids, with its own approvals and cleaning regime.
- Ventilated — passive vents along the top rail. Used for cargo that respires, though for anything temperature-sensitive a reefer is the answer.
What limits you first
Every container has two ceilings: cubic capacity and payload. Which one you hit first depends entirely on the density of what you are shipping, and it decides how you should be buying freight.
| Cargo | Limited by | Consequence |
|---|---|---|
| Natural rubber, carbon black | Weight | The box is nowhere near full when you reach maximum payload. A 20ft is often the right unit. |
| Newsprint reels | Weight, usually | Dense, and floor loading and reel diameter both constrain the stow. |
| Coir pith, coir mats | Volume | The box fills long before it is heavy. Compression and baling directly change your freight cost per tonne. |
| Cashew kernel, spices | Volume, generally | Packaging efficiency matters more than the box rating. |
| Machinery and spares | Either | Depends entirely on the item. Worth calculating rather than assuming. |
If you are volume-limited, you are paying to ship air, and the fix is packing. If you are weight-limited, larger boxes gain you nothing and you should be comparing the cost per tonne rather than per container.
The Indian road limit
The number stamped on the container is what the box can carry. It is not necessarily what you can legally move on the road between the port and your factory.
Permissible laden weight for a road vehicle depends on the axle configuration of the trailer, and it frequently binds well before the container's own rating does. A container legally loaded at origin to near its maximum gross can arrive at Cochin and require special arrangements — or a different trailer — to move inland.
This is a recurring and expensive surprise for first-time importers of dense cargo. If your consignment is heavy, tell us the intended gross weight before the container is stuffed at origin. Sorting out the trailer configuration in advance costs a phone call; sorting it out with a loaded box sitting at the port costs storage, detention and a lost week.
Choosing between 20ft and 40ft
A 40ft container holds roughly twice the volume of a 20ft but carries only slightly less weight in total, because the tare of the bigger box eats into the same 30,480 kg gross limit. That produces a simple rule of thumb.
- Dense cargo — two 20ft boxes will carry substantially more total weight than one 40ft. Freight per container is higher, but per tonne it usually wins.
- Light or bulky cargo — one 40ft, or a high cube, will almost always beat two 20ft on cost, and gives you a single unit to handle.
- Handling constraints — a 40ft trailer needs room to turn and reverse. Some factory yards in Kerala simply cannot take one, which settles the question regardless of the economics.
Where it is close, ask us to run both. We do this calculation weekly and it takes minutes.
Common questions
What is the difference between a 40ft and a 40ft high cube?
One foot of internal height, which gives roughly nine extra cubic metres. High cubes are standard on most trades now. They matter for volume-limited cargo and for anything tall being loaded upright.
How much weight can a 20ft container actually carry?
Typically around 28 tonnes of payload against a 30,480 kg maximum gross, though the plate on the individual box governs. Indian road limits often reduce what you can move inland below what the box can legally hold at sea.
Is a 20ft container really half a 40ft?
In volume, roughly. In weight, no. Both share a similar maximum gross mass, so two 20ft boxes carry far more total payload than a single 40ft. This is why dense cargo tends to ship in 20ft units.
Do I need a reefer or will a ventilated container do?
If the cargo needs a controlled temperature, it needs a reefer. Ventilated containers only allow passive air exchange and cannot hold a set point. For seafood and most produce out of Cochin, the answer is a reefer.