The CBM formula
CBM per carton = length (m) × width (m) × height (m) Line CBM = CBM per carton × number of cartons Shipment CBM = sum of every line
Always measure the outside of the carton, including any bulge, and convert every dimension to metres before multiplying. If you multiply in centimetres or inches, divide by the right conversion factor at the end.
Example in metres
0.60 m × 0.40 m × 0.35 m = 0.084 m³ per carton 0.084 × 120 cartons = 10.08 CBM
Example in centimetres
Multiply the three centimetre values and divide by 1,000,000 (the number of cm³ in one m³).
60 cm × 40 cm × 35 cm = 84,000 cm³ 84,000 ÷ 1,000,000 = 0.084 m³ per carton
Example in millimetres
Multiply the millimetre values and divide by 1,000,000,000.
600 mm × 400 mm × 350 mm = 84,000,000 mm³ 84,000,000 ÷ 1,000,000,000 = 0.084 m³
Example in inches and feet
One inch is exactly 0.0254 m, so one cubic inch is 0.000016387 m³. Multiply the inch dimensions and divide by 61,023.7.
24 in × 16 in × 14 in = 5,376 in³ 5,376 ÷ 61,023.7 = 0.0881 m³ per carton
Working in feet, multiply the dimensions in feet to get cubic feet, then divide by 35.3147.
2 ft × 1.5 ft × 1 ft = 3 ft³ 3 ÷ 35.3147 = 0.0850 m³
Example with mixed cartons
Work out each carton size separately, then add the lines together.
| Carton | Size (cm) | Qty | CBM per carton | Line CBM |
|---|---|---|---|---|
| Shoes | 60 × 40 × 35 | 120 | 0.084 | 10.08 |
| Bags | 50 × 40 × 30 | 75 | 0.060 | 4.50 |
| Clothing | 45 × 35 × 25 | 240 | 0.039375 | 9.45 |
| Total | 24.03 CBM | |||
Common mistakes
- Mixing units, such as length in centimetres and height in inches.
- Rounding each carton too early. Keep the full figure per carton and round only the final total.
- Using the product's size instead of the shipping carton's outside size.
- Treating total CBM as the space you will need. Cartons cannot be split, so pallets and containers rarely fill completely; the Container Loading Calculator shows how cartons really fit.
To skip the arithmetic, enter your cartons in the CBM Calculator. It accepts mm, cm, m, inches and feet, mixes units per line and shows every step. If you are not sure what CBM is used for, start with What Is CBM?