What CBM is, and when you need it
CBM (a cubic metre) is how freight measures volume: a box 1 m long, 1 m wide and 1 m high.
- You need it before any quote. Forwarders price LCL (less than container load) sea freight by the cubic metre, and air and road carriers weigh it against the actual weight.
- It gives a first idea of the container: a 20 ft container holds about 33 m³ inside, a 40 ft about 68 m³. Cartons stack in whole rows, so fewer fit than the volume suggests: the container loading calculator counts them.
- The density, kilograms per cubic metre, says whether a carrier will bill the cargo on its volume or on its weight.
How to calculate CBM (the formula)
- Measure the packed carton at its widest points: length, width, height.
- Put the three sides in metres.
- Multiply them, then multiply by the number of cartons. Add the lines together.
CBM of one carton = length × width × height, in metres
from centimetres: L × W × H ÷ 1,000,000
from millimetres: L × W × H ÷ 1,000,000,000
from inches: L × W × H × 16.387064 ÷ 1,000,000
total CBM = CBM of one carton × cartons, added over every line
cubic feet = CBM ÷ 0.028316846592
density = total weight in kg ÷ total CBM
An inch is exactly 2.54 cm, so a cubic inch is 16.387064 cm³, and a cubic foot is exactly 0.028316846592 m³ (NIST, the US National Institute of Standards and Technology).
Worked example: the CBM of 50 cartons
The calculator starts with it.
- 50 cartons, each 60 × 40 × 40 cm and 12 kg.
- One carton: 0.6 × 0.4 × 0.4 = 0.096 m³.
- All 50: 0.096 × 50 = 4.8 m³, or 169.51 ft³.
- Weight: 12 × 50 = 600 kg.
- Density: 600 ÷ 4.8 = 125 kg/m³. Every mode counts a cubic metre as more than that (air as 166.67 kg), so every mode bills this cargo on its volume: the chargeable weight calculator works out what each would bill.
CBM to cubic feet (CFT) and other units
| This | Is |
|---|---|
| 1 m³ (CBM) | 35.31 ft³ (CFT) |
| 1 m³ (CBM) | 1,000,000 cm³ |
| 1 m³ (CBM) | 61,024 in³ |
| 1 ft³ (CFT) | 0.0283 m³ |
How many CBM does a container hold?
The inside of each container, on the typical sizes the tools use. You can load somewhat less, as cartons stack in whole rows: the container loading calculator counts how many fit.
| Container | Inside, L × W × H (m) | CBM |
|---|---|---|
| 20 ft container (20' GP) | 5.9 × 2.352 × 2.393 | 33.2 m³ |
| 40 ft container (40' GP) | 12.032 × 2.352 × 2.395 | 67.8 m³ |
| 40 ft high cube (40' HC) | 12.032 × 2.352 × 2.7 | 76.4 m³ |
| 45 ft high cube (45' HC) | 13.556 × 2.352 × 2.7 | 86.1 m³ |
CBM of common carton sizes
| Carton | CBM | Cubic feet |
|---|---|---|
| 40 × 30 × 30 cm | 0.036 m³ | 1.27 ft³ |
| 50 × 40 × 30 cm | 0.06 m³ | 2.12 ft³ |
| 60 × 40 × 40 cm | 0.096 m³ | 3.39 ft³ |
| 60 × 50 × 50 cm | 0.15 m³ | 5.3 ft³ |
| 80 × 60 × 60 cm | 0.288 m³ | 10.17 ft³ |