Choosing the wrong container means either paying for empty space or leaving cargo behind at the port. A few numbers are enough to choose correctly, as long as you remember that the space you can really use is always less than the theoretical volume.
A standard 20ft container holds about 33 CBM in theory, but around 25 to 28 CBM of cartons in practice. A 40ft container holds about 67 CBM, with 55 to 58 CBM usable. A 40ft high cube is about 30 cm taller, holds about 76 CBM, and around 65 to 68 CBM usable. Heavy cargo such as stone, metal or grain often reaches the weight limit before the container is full.
Typical internal dimensions
| Container | Internal L x W x H (approx.) | Volume | Usable for cartons |
|---|---|---|---|
| 20ft standard | 5.90 x 2.35 x 2.39 m | ~33 CBM | ~25 to 28 CBM |
| 40ft standard | 12.03 x 2.35 x 2.39 m | ~67 CBM | ~55 to 58 CBM |
| 40ft high cube | 12.03 x 2.35 x 2.69 m | ~76 CBM | ~65 to 68 CBM |
Exact figures vary between container owners. Ask your shipping line or freight forwarder for the specification of the container you are booking.
Why usable space is lower
Cartons rarely fit the container walls exactly. You lose space at the edges and the top, and you may need room for pallets, dunnage or air bags that stop the cargo moving. Fragile goods cannot always be stacked to the roof. Planning on about 80 to 85% of the theoretical volume is a safe starting point.
Watch the weight limit
Each container has a maximum gross weight, which covers the container itself plus cargo. The cargo you can load depends on the container and on road weight rules in India and at the destination. Dense cargo such as rice, marble, tiles or metal parts often fills the weight allowance long before the space. A 20ft container is often the better choice for heavy goods, and a 40ft or high cube suits light, bulky goods such as furniture, garments or handicrafts. Always confirm the allowed payload with your forwarder.
How many cartons will fit
Divide the usable volume by the volume of one carton for a rough count. For example, a carton of 50 x 40 x 40 cm is 0.08 CBM, so about 25 CBM of usable space in a 20ft container holds around 310 cartons. The real number depends on how the cartons line up with the container walls. Our free CBM calculator works out the volume of your cartons and how they fit in a 20ft, 40ft or high cube container.
FCL or LCL?
If your cargo fills less than about half of a 20ft container, sharing a container through LCL is usually cheaper. Our guide to FCL vs LCL shipping explains how to decide.
Frequently asked questions
How many CBM is a 20ft container?
About 33 CBM of internal volume, with around 25 to 28 CBM usable for cartons in practice.
How many CBM is a 40ft container?
About 67 CBM for a standard 40ft and about 76 CBM for a 40ft high cube. Usable space is lower, around 55 to 58 and 65 to 68 CBM respectively.
Is a 40ft container twice the price of a 20ft?
Usually not. A 40ft container often costs noticeably less than two 20ft containers, which makes it better value for light, bulky cargo.
What is a high cube container?
A 40ft high cube is about 30 cm taller than a standard 40ft container, giving roughly 9 to 10 CBM more space for tall or light cargo.
Check your container load
Enter your carton size, weight and quantity to see the total CBM and how it fits into a 20ft, 40ft or high cube container.
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