What CBM means in shipping
CBM is cubic meters: the space your cargo takes. Forwarders price loose sea freight (LCL) by it, and it decides whether a full container is the cheaper way to ship.
Free shipping tool
CBM calculator for shipping
Work out the cubic meters of your cartons in seconds, and how many of them fit in a 20 ft, 40 ft or high cube container. Save the back-and-forth with forwarders: know your volume before you ask for a price.
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- Inches or centimetres
- Container fit checked against weight
Free to use. When you want real prices, posting a shipment is free too: no credit card, and nothing is booked until you accept a bid.
One carton
Total volume
9.6 CBM
- Cubic feet
- 339
- One carton
- 0.096 CBM
- Total weight
- 1,200 kg · 2,646 lb
How many cartons fit: container loading calculator
Laid in rows, turned where that fits more, stacked as high as the box allows, and stopped at the weight limit.
| Container | Cartons | Containers for 100 | Limited by |
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Loading the containers…
Rules of thumb
- Measure the outside of the carton, at its widest, including any bulge or handle.
- Round each side up to the next centimetre or half inch: carriers measure, and they round up.
- Count the cartons you will actually ship, not the units inside them.
- Weigh a packed carton rather than adding up the product weights: packaging and fill add more than you expect.
- If the cartons go on pallets, measure the built pallet as one unit, with the pallet itself.
Related
- DDP calculatorThe billed weight and what a duty-paid price is made of.
- Container dimensionsInside sizes, payloads and pallet counts.
- Containers from ChinaFull and shared containers, bid on by carriers.
- Amazon FBA freightCartons straight into a fulfilment centre.
How it works
The CBM calculator, explained
The CBM formula
Multiply length by width by height in meters, then by the number of cartons. A carton of 60 × 40 × 40 cm is 0.6 × 0.4 × 0.4 = 0.096 CBM; 100 of them are 9.6 CBM. In inches, multiply the three sides and divide by 61,024.
From CBM to how many cartons fit
Volume alone overstates it: cartons are rigid and the walls are where they are. The calculator lays the floor out in rows, turning cartons where that fits more, stacks as many layers as the height allows, and stops at the container’s weight limit. A real load often takes a few fewer, to leave room at the door.
CBM in cubic feet and cubic inches
One cubic meter is 35.3147 cubic feet or 61,024 cubic inches. US suppliers often quote cartons in inches: multiply the three sides in inches and divide by 1,728 for cubic feet, or by 61,024 for CBM. The calculator does either when you switch to inches and pounds.
Why the weight matters too
A container has a weight limit as well as a volume. Ceramic tiles, books or metal parts reach the limit long before the box is full, so the calculator checks both and says which one stops the load. Dense cargo is usually cheaper in a 20 ft box, which carries nearly as much weight as a 40 ft.
Loose cargo or a full container
Below a few cubic meters, your cartons share a container with other shippers’ (LCL) and you pay for the space you take. As the volume grows, a container of your own (FCL) starts to cost about the same and moves faster, with fewer handlings. The result box says when your volume is still in loose-cargo territory.
CBM for Amazon FBA cartons
Amazon sets its own limits on the size and weight of each carton sent into a fulfilment centre, and has changed them before. Check the current limits in Seller Central before you pack, then measure the packed cartons for the CBM. On Ebbrate, cartons for Amazon go only to carriers approved to deliver into fulfilment centres on your lane.
From CBM to a price
Carriers bill the greater of the actual and the volumetric weight. The DDP calculator shows that billed weight and what a duty-paid price is made of; posting the shipment on Ebbrate gets you real bids from verified carriers.
How to use the CBM calculator, step by step
- Measure one carton on the outside: length, width and height, at the widest points.
- Convert each side to meters: 60 cm is 0.6 m; 24 inches is 0.6096 m.
- Multiply the three: 0.6 × 0.4 × 0.4 = 0.096 CBM for one carton.
- Multiply by the number of cartons: 100 cartons are 9.6 CBM.
- Add the other carton sizes in the shipment the same way, and add the results together.
Mistakes that make a CBM wrong
- Measuring the product instead of the packed carton.
- Using the supplier’s quoted carton size without checking a packed one: cartons bulge once filled.
- Mixing inches and centimetres across lines of the same shipment.
- Forgetting the pallet: a palletised shipment is measured as built, pallet included.
- Rounding down. Carriers re-measure at the warehouse and bill the larger size.
CBM calculator: common carton sizes
| Carton | CBM each | Cubic feet each | CBM for 100 |
|---|---|---|---|
| 40 × 30 × 30 cm | 0.036 | 1.27 | 3.6 |
| 50 × 40 × 40 cm | 0.08 | 2.83 | 8 |
| 60 × 40 × 40 cm | 0.096 | 3.39 | 9.6 |
| 60 × 40 × 50 cm | 0.12 | 4.24 | 12 |
| 18 × 18 × 18 in | 0.0956 | 3.37 | 9.56 |
| 24 × 18 × 18 in | 0.1274 | 4.5 | 12.74 |
Sources
- NIST: unit conversion (metric and US customary)
- ISO 668:2020, series 1 freight containers (Standards Council of Canada listing)
Reviewed by the Ebbrate editorial team, 17 October 2026.
Questions
CBM questions
How do I calculate CBM for shipping?
Length × width × height of one carton, in meters, times the number of cartons. Measure the outside of the carton, including any bulge.
How many cubic feet are in a CBM?
One cubic meter is 35.3147 cubic feet. To go the other way, divide cubic feet by 35.3147.
Is CBM the same as volumetric weight?
No. CBM is volume. Volumetric weight turns that volume into a weight with a divisor, and carriers bill whichever of the actual and volumetric weight is greater.
When is a full container cheaper than LCL?
It depends on the lane and the season, but past roughly half a 20 ft container a full one is often worth pricing. On Ebbrate you can post it as either and compare the bids.
How do I measure a carton correctly?
At its outside, at the widest point, including any bulge. Round each side up: carriers re-measure at the warehouse, and a carton that grew is billed at the larger size.
Does pallet height count in CBM?
Yes. A palletised shipment is measured as built: the pallet itself, usually about 15 cm high, plus the cartons stacked on it.
How many CBM fit in a 20 ft or 40 ft container?
The capacities are on the container dimensions page. Cartons never fill all of it: rigid boxes leave gaps against the walls and the roof, which is why the calculator counts cartons instead of dividing volumes.
Know your CBM? Get real bids for your cargo
You have the numbers from the CBM calculator. Post the shipment free: verified carriers bid against each other, every bid split by leg, and you never have to accept.