CBM Calculator — Cubic Meter for Shipping, CFT & Container Loading
Calculate the CBM (cubic metres) of your cartons in cm, mm, inches or feet. Get total CBM and CFT, sea and air chargeable weight, how many 20 ft or 40 ft containers you need, how many cartons fit in each, and an LCL freight estimate.
What is CBM?
CBM stands for cubic metre (m³), the standard unit of volume in international shipping. One CBM is a box 1 m long, 1 m wide and 1 m high. Freight forwarders use it to price sea freight (especially LCL, shared-container shipments), plan container loading and work out volumetric weight for air cargo. It is the most important number on a packing list after the product count.
CBM calculation formula
Dimensions in cm: L × W × H ÷ 10,00,000
Dimensions in mm: L × W × H ÷ 1,00,00,00,000
Dimensions in inches: L × W × H ÷ 61,024
Dimensions in feet: L × W × H ÷ 35.315
Worked examples
| Carton | Working | CBM per carton |
|---|---|---|
| 60 × 40 × 50 cm | 1,20,000 cm³ ÷ 10,00,000 | 0.120 |
| 50 × 40 × 30 cm | 60,000 cm³ ÷ 10,00,000 | 0.060 |
| 24 × 18 × 20 inch | 8,640 in³ ÷ 61,024 | 0.1416 |
| 2 × 1.5 × 1.5 ft | 4.5 CFT ÷ 35.315 | 0.1274 |
A mixed shipment: 120 cartons of 60 × 40 × 50 cm (14.40 CBM) plus 40 cartons of 80 × 60 × 45 cm (8.64 CBM) makes 23.04 CBM, or 813.65 CFT. That fits in one 20 ft container at about 69% of its internal volume, which is close to the practical limit once packing gaps are allowed for.
Always measure the outer dimensions of the carton, at the widest point including any bulge, and round up to the nearest centimetre. Forwarders re-measure at the warehouse, and the larger figure is what you pay for.
CBM to CFT conversion
In India, road transporters and many warehouses quote in CFT (cubic feet), while ocean freight is quoted per CBM.
| Unit | Equals |
|---|---|
| 1 CBM | 35.3147 CFT · 61,023.7 cubic inches · 1,000 litres |
| 1 CFT | 0.0283 CBM · 1,728 cubic inches · 28.32 litres |
| 10 CBM | 353.15 CFT |
| 100 CFT | 2.83 CBM |
Chargeable weight: sea, air and courier
Carriers charge on volume or weight, whichever is higher, because a truckload of pillows and a truckload of steel take the same space but very different effort. Each mode uses a different conversion:
| Mode | Volumetric rule | 1 CBM equals | You pay on |
|---|---|---|---|
| Sea LCL | 1 CBM = 1 revenue ton (W/M) | 1,000 kg | Higher of CBM or tonnes, usually 1 RT minimum |
| Air cargo | L × W × H (cm) ÷ 6,000 | 166.67 kg | Higher of actual or volumetric kg |
| Express courier | L × W × H (cm) ÷ 5,000 | 200 kg | Higher of actual or volumetric kg |
| Sea FCL | Price per container | - | Box rate, within the payload limit |
Domestic surface couriers in India use their own divisors, so check your rate card. The cargo density tile in the calculator shows whether a shipment is "heavy" (over 1,000 kg per CBM, charged by weight at sea) or "light" (under about 167 kg per CBM, charged by volume by air).
Container sizes and capacity
| Container | Internal L × W × H | Volume | Practical load | Typical max payload |
|---|---|---|---|---|
| 20 ft standard (20GP) | 5.898 × 2.352 × 2.393 m | 33.2 CBM | ~25–28 CBM | ~28,000 kg |
| 40 ft standard (40GP) | 12.032 × 2.352 × 2.393 m | 67.7 CBM | ~55–58 CBM | ~26,600 kg |
| 40 ft high cube (40HC) | 12.032 × 2.352 × 2.698 m | 76.3 CBM | ~65–68 CBM | ~26,500 kg |
Exact dimensions and payload vary slightly by container owner and age, and the door opening (about 2.34 × 2.28 m on a standard box) is smaller than the interior. Road weight limits for the truck carrying the container in India can also be lower than the container's payload, so for heavy cargo, confirm the allowed gross weight with your transporter.
How many cartons fit in a container?
Stacked in a single orientation (no mixing):
| Carton size | 20GP | 40GP | 40HC |
|---|---|---|---|
| 60 × 40 × 50 cm (0.12 CBM) | 180 | 400 | 500 |
| 50 × 40 × 30 cm (0.06 CBM) | 392 | 840 | 1,050 |
| 40 × 30 × 30 cm (0.036 CBM) | 686 | 1,470 | 1,680 |
The high cube's extra 30 cm of height adds a whole layer for many carton sizes, which is why a 40HC often costs only slightly more than a 40GP but can carry about 12–25% more cartons. For cartons that must stay upright, tick This side up in the calculator.
LCL or FCL: which should you book?
- LCL (Less than Container Load): you pay per CBM or RT and share the container. Best for small shipments, typically under about 13–15 CBM. Expect extra CFS handling charges at both ends and a longer transit time for consolidation.
- FCL (Full Container Load): you book the whole box. Above about 13–15 CBM a 20 ft container often costs about the same as LCL, with less handling, lower damage risk and faster delivery.
- Air: for urgent, high-value or light cargo. Compare its chargeable weight (÷6,000) against the sea option.
Tips to cut your CBM and freight bill
- Right-size cartons. Empty space inside cartons is paid for at the full freight rate.
- Pick carton sizes that divide the container. A carton length that fits the 2.352 m width exactly (for example 39 cm × 6, or 58.5 cm × 4) avoids wasted space along the walls.
- Palletise only when needed. Pallets protect goods but add 12–15 cm per layer and take up floor space.
- Declare accurate CBM on the packing list. Re-measurement at the CFS leads to revised invoices and possible delays.
- Check customs too. Freight and insurance form part of the assessable value for import duty. Estimate the full landed cost with our Customs Duty Calculator.
