CBM and chargeable weight calculator
Type in one carton and how many you have. This works out your total CBM, what air, express and ocean will each bill you on, and how many cartons fit in a container before you either cube out or weigh out. No sign-up, no email, and no invented freight rates.
The numbers behind the arithmetic
Nothing on this page is a house estimate. The divisors are industry standard and the container figures are published specifications, rounded.
| Container | Internal volume | Maximum payload |
|---|---|---|
| 20ft standard | 33.2 CBM | 28,000 kg |
| 40ft standard | 67.7 CBM | 26,500 kg |
| 40ft high cube | 76.3 CBM | 26,330 kg |
- Air uses a 6000 divisor. That is the IATA standard: volumetric kg equals length by width by height in centimeters, divided by 6000.
- Express couriers commonly use 5000. Same arithmetic, a smaller divisor, so bulky shipments cost more. Ask which one applies before you book.
- Ocean LCL bills the revenue ton. The greater of your CBM or your metric tons, treating one CBM as 1,000 kg. Written W/M on most quotes.
- Container specs vary. Internal volume and payload differ by a few hundred kilos between builds and carriers, and the payload you actually get also depends on road weight limits at the destination.
Container sizes, capacity and what will actually fit
Internal dimensions and cubic capacity as the carriers publish them, next to the two numbers that decide your real load: the volume you can plan on once cartons stop tessellating, and the weight a truck can legally carry away from the port.
| Container | Internal L × W × H (mm) | Capacity | Plan at 85% | Carrier max payload | Typical US road limit |
|---|---|---|---|---|---|
| 20ft standard | 5,900 × 2,352 × 2,395 | 33.2 CBM | 28.2 CBM | 28,130 kg | 20,330 kg |
| 40ft standard | 12,032 × 2,352 × 2,395 | 67.7 CBM | 57.5 CBM | 28,750 kg | 18,930 kg |
| 40ft high cube | 12,032 × 2,350 × 2,700 | 76.3 CBM | 64.9 CBM | 28,600 kg | 18,780 kg |
| 45ft high cube | 13,556 × 2,352 × 2,700 | 86.0 CBM | 73.1 CBM | 27,700 kg | 17,880 kg |
Dimensions, capacity and payload as published by Hapag-Lloyd for its own dry containers. Other carriers' boxes differ slightly; if a few hundred kilos or a few centimeters would change your plan, ask for the specification of the exact container booked.
Why the payload column is not the number you can use
A 40ft container is rated to carry roughly 28,750 kg. Almost no US importer ever loads that much, and the reason is the drive from the port, not the ship.
Federal law caps a truck at 80,000 lb gross on the interstate system. A five-axle tractor and container chassis weighs about 30,000 lb empty. The container itself has a tare weight. What is left is your cargo:
- 80,000 lb legal gross, minus
- 30,000 lb of tractor and chassis, minus
- 8,267 lb of empty 40ft container, leaves
- about 41,700 lb, roughly 18,900 kg of cargo.
That is around two thirds of what the box is rated for. You can go heavier with an overweight permit, a tri-axle chassis, or a port with a short local route, and all three cost money and have to be arranged before the container is packed rather than after it lands. State limits and permitted routes vary, so treat the column above as a planning figure and confirm the lane.
The practical version: if your cargo is dense, book more containers and load them lighter. Discovering the problem at the terminal means paying storage while it is stripped and reloaded.
How many cartons fit in a container
Worked for a common export carton of 60 × 40 × 40 cm, which is 0.096 CBM each. The first column is the arithmetic. The second is what loads.
| Container | Capacity | On paper | Realistic |
|---|---|---|---|
| 20ft standard | 33.2 CBM | 345 | 293 |
| 40ft standard | 67.7 CBM | 705 | 599 |
| 40ft high cube | 76.3 CBM | 794 | 675 |
| 45ft high cube | 86.0 CBM | 895 | 761 |
The gap between the two columns is not waste, it is physics. Cartons do not divide evenly into a container's dimensions, pallets give up height to their own deck, and a loader needs room to work and to brace the load so it survives the sea.
Eighty-five percent is a reasonable planning assumption for palletized cargo. Floor-loaded cartons of one uniform size, hand-stacked, can reach ninety and occasionally beyond. Mixed carton sizes rarely do. Change your own carton dimensions in the calculator above and it works this out for your actual box.
Now it can be quoted honestly
Chargeable weight is what a forwarder needs before anyone can price your shipment without guessing. Send us the number this page gave you, tell us what is in the boxes and where it is going, and we will come back with a real quote and a straight opinion on whether air is worth it.
Frequently asked
What is CBM, and how do I calculate it?
Cubic meters, the volume your cargo occupies. One CBM is a cube one meter on every side. Multiply a carton's length by its width by its height in centimeters, divide by 1,000,000, and multiply by how many cartons you have. Ocean freight is quoted in CBM, so it is the number every forwarder asks for first.
What is chargeable weight, and why is it higher than what my cargo weighs?
Carriers sell space as much as they sell lift, so a light bulky shipment is billed on the space it takes rather than what it weighs. Chargeable weight is whichever is greater: the actual gross weight, or a volumetric weight worked out from the dimensions. Pillows and phone cases almost always bill on volume. Machine parts almost always bill on weight.
Which volumetric weight divisor should I use, 6000 or 5000?
6000 is the IATA standard and what a normal air freight forwarder will use. Many express couriers divide by 5000 instead, which makes bulky shipments cost more. The calculator shows both, because the difference between them changes the answer often enough to matter. Confirm which one your carrier applies before you book.
How is ocean LCL charged?
On the revenue ton, sometimes written W/M for weight or measurement: the greater of your total CBM or your total weight in metric tons, treating one CBM as 1,000 kg. Most consumer goods bill on volume. Anything dense, like liquids, hardware or ceramics, can flip to weight.
How many cartons fit in a 20ft or 40ft container?
Fewer than the raw volume suggests. Cartons do not tessellate perfectly, pallets waste height, and you need room to load and brace. Planning at 85 percent of the internal volume is a reasonable starting assumption for palletized cargo, and the calculator lets you change it. Floor-loaded cartons of one uniform size can beat that. Mixed sizes rarely do.
Should I cube out or weigh out?
You want to hit both limits at once, which almost never happens. The calculator shows which limit you hit first. If you cube out with tons of payload spare, denser packaging or a smaller carton is worth real money. If you weigh out with space left, you are paying to ship air in the remaining volume and may want to split the order across shipments.
Do these numbers give me a freight cost?
No, and be suspicious of any calculator that says it does. Chargeable weight is the arithmetic; the rate you multiply it by moves week to week and depends on lane, season, and what you are shipping. What this page gives you is the number a forwarder needs before anyone can quote you honestly. Send it to us and we will come back with a real one.
What is the CBM capacity of a 20ft container?
About 33 CBM of internal volume for a standard 20ft, roughly 67 for a 40ft and about 76 for a 40ft high cube. Those are the box dimensions, not what you will actually load. Plan against 85 percent of them for palletized cargo, because cartons do not tessellate perfectly, pallets waste height, and you need room to load and brace. The calculator uses that same allowance and lets you change it.
Send us the shipment
Carton size, carton count, what is inside and the port or door it needs to reach. That is enough for a real quote rather than a range.
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