CBM calculator
A CBM calculator for cartons: length times width times height times quantity, in centimetres or inches. The total is cubic metres and cubic feet. It also shows the sea weight-or-measure equivalent, where 1 CBM equals 1,000 kg, and whether that cube fits the published example capacity of a 20 ft, 40 ft or 40 ft high-cube container. The result is an estimate. The carrier and the box decide what actually loads.
How the calculation works
Cubic metres for one line are the three sides in metres, multiplied, then multiplied by quantity. In centimetres that is length × width × height × quantity, divided by 1,000,000. Inches are converted to centimetres with 2.54 centimetres per inch before the same division. Add the lines to get the shipment CBM.
Cubic feet use the same cube. Each side in centimetres is divided by 2.54 to reach inches, the cubic inches are divided by 1,728, and the lines are added. The page shows CBM rounded half up to three decimal places and cubic feet rounded half up to two decimal places. The fit check uses the unrounded total, so display rounding cannot push a shipment over a capacity on its own.
CBM to kg on this page is that unrounded total multiplied by 1,000. It is the volume side of sea weight or measure, the same 1 CBM = 1,000 kg convention as the chargeable weight calculator. It is not chargeable weight, because chargeable weight also needs the actual kilograms and then rounds the greater figure up. There is no weight field here.
The fit rows compare the unrounded CBM with example capacities published by Hapag-Lloyd: 33.2 CBM for a 20 ft standard, 67.7 CBM for a 40 ft standard, 76.3 CBM for a 40 ft high cube, and 86.0 CBM for a 45 ft high cube. A fit means the cube is within that published capacity. It does not check payload, door size, dunnage or mixed stow. Exact figures vary by box and carrier.
A shared result keeps the unit and the carton lines in the page address. The query string has no name, postcode or goods description. Copy result puts the rounded CBM, the rounded cubic feet, the volume kilograms and each fit line on the clipboard. Opening that address again restores the same lines.
Container loading is the next step when you need a count of pieces rather than a cube. It places cartons on a grid and can stop on payload. This page does not. Linear feet answers the same kind of question for a trailer. The shipping container sizes guide cites the 33.2, 67.7, 76.3 and 86.0 CBM examples with internal dimensions, door openings and payload, and it leaves out the 40 ft tare because the kilogram cell on that source page is ambiguous.
Metric worked example. Ten cartons of 60 × 40 × 40 centimetres are 0.96 CBM. Four cartons of 50 × 40 × 30 centimetres are 0.24 CBM. Together they are 1.200 CBM, which is 1,200 kg at 1,000 kg per CBM. That cube is inside every example capacity on the table. Imperial worked example. Two cartons of 48 × 40 × 36 inches are 138,240 cubic inches, which is 80 cubic feet. The CBM for those inches uses 2.54 centimetres per inch, so it is the same cube rather than a second measurement.
Last checked 16 October 2026. Carton maths uses 2.54 cm per inch and 1,728 cubic inches per cubic foot from the formula config. Sea weight or measure treats 1 CBM as 1,000 kg. Container capacities are Hapag-Lloyd examples, last checked 19 October 2026.
Cubic metres and cubic feet
Cubic metres are the carton cube. Cubic feet are the same cube after converting with 2.54 centimetres per inch and dividing by 1,728 cubic inches. Both totals are on the result.
CBM to kg
Multiply CBM by 1,000 for the sea volume equivalent in kilograms. The capacities are Hapag-Lloyd’s published examples. Exact figures vary by box and carrier. Last checked: 19 October 2026.
| Example | Capacity | Source |
|---|---|---|
| 20 ft | 33.2 CBM | Hapag-Lloyd 20' standard |
| 40 ft | 67.7 CBM | Hapag-Lloyd 40' standard |
| 40 ft HC | 76.3 CBM | Hapag-Lloyd 40' standard high cube |
| 45 ft HC | 86 CBM | Hapag-Lloyd 45' standard high cube |
Worked examples
Metric cartons
Ten cartons of 60 × 40 × 40 cm and four of 50 × 40 × 30 cm.
- CBM
- 1.2
- Cubic feet
- 42.38
- Volume kg
- 1,200
Imperial cartons
Two cartons of 48 × 40 × 36 in.
- CBM
- 2.265
- Cubic feet
- 80
- Volume kg
- 2,265
Questions
How do you calculate CBM?
Multiply length, width and height in metres, then multiply by the number of cartons. From centimetres, divide the product by 1,000,000. Add each carton line. The displayed total is rounded half up to three decimal places.
How do I convert CBM to kg?
For sea weight or measure, multiply CBM by 1,000. That is a volume equivalent in kilograms, not the weight on the scale, and not a freight rate. Chargeable weight uses the greater of that figure and the actual weight.
How do cubic metres convert to cubic feet?
The page converts the centimetre cube to cubic inches with 2.54 centimetres per inch, then divides by 1,728. The displayed cubic feet are rounded half up to two decimal places.
Will this cargo fit in a 20 ft or 40 ft container?
The indicator compares your CBM with Hapag-Lloyd example capacities: 33.2 for a 20 ft, 67.7 for a 40 ft and 76.3 for a 40 ft high cube. Fitting the cube is not the same as fitting through the door or staying under the payload.
Can I mix carton sizes?
Yes. Add a line for each size, with its own length, width, height and quantity. The total is the sum of the lines. Switch the unit toggle and every line converts together.
Is the CBM a freight quote?
No. It is the cube of the cartons you typed, plus a volume check against published example capacities. Carriers bill on their own rules.