What is CBM calculation?
CBM (Cubic Meter) is the international logistics standard unit for expressing cargo volume (1 CBM = 1 m³). It is the most fundamental basis for calculating freight in ocean and air forwarding, and the CBM of a single box is calculated as length (m) × width (m) × height (m). This calculator takes box dimensions in cm and automatically converts them to meters to produce the total CBM.
Example — the total CBM of 50 boxes measuring 60cm (L) × 40cm (W) × 40cm (H) is (0.6 × 0.4 × 0.4) × 50 = 4.8 CBM.
LCL vs. FCL selection guide
LCL (Less than Container Load)
- Consolidated shipping in which multiple shippers share one container
- Freight is calculated based on CBM and weight
- Generally advantageous for cargo of 15 CBM or less
- Lead time is somewhat longer due to added consolidation and customs work
FCL (Full Container Load)
- Exclusive use of an entire container (20ft DC · 40ft DC · 40HC)
- Flat rate per container — the higher the utilization, the lower the unit cost
- Generally advantageous for cargo of 15 CBM or more, or where security and schedule matter
- Easier door-to-door schedule management
RUNIC international forwarding handles both LCL and FCL quotes, covering everything from domestic pickup and post-pickup storage to ocean, air, customs clearance, and inland transport with a single team. Pre-checking with this CBM calculator before requesting a quote allows for more accurate freight estimates.
20ft DC · 40ft DC · 40HC container standard specifications
| Container | Internal dimensions (L × W × H) | Usable capacity | Max payload |
|---|
| 20ft DC | 5.89 × 2.35 × 2.39 m | approx. 28 CBM | approx. 28 tons |
| 40ft DC | 12.03 × 2.35 × 2.39 m | approx. 58 CBM | approx. 28 tons |
| 40ft HC | 12.03 × 2.35 × 2.69 m | approx. 68 CBM | approx. 28 tons |
Usable capacity varies with box shape, weight distribution, and cushioning materials, and 80–85% utilization is typical in actual shipping. The maximum payload may vary somewhat depending on the container's own weight and road transport regulations.
Frequently asked questions
What is the formula for calculating CBM?
CBM per box = length (m) × width (m) × height (m). If the dimensions are in cm, divide by 1,000,000 to convert to m³. Total cargo CBM = CBM per box × quantity.
What is volumetric weight?
In air and international express shipping, the greater of the actual weight and the volumetric weight is used as the basis for calculating freight. The common air conversion formula is volumetric weight (kg) = CBM × 167. Light but bulky cargo is charged by volumetric weight, which can raise the freight cost.
How do you decide between LCL and FCL?
Typically, up to 15 CBM is more economical as LCL and above that as FCL. However, this can vary with cargo characteristics, schedule sensitivity, security requirements, and destination infrastructure, so we recommend a quote consultation.
What happens if a box exceeds the container dimensions?
If a single box exceeds the container's internal dimensions, it cannot be loaded into that container. You will need to split the box or consider a larger size (e.g., 40HC), and special cargo requires OOG (Out of Gauge) shipping to be arranged separately.
How do you calculate how many boxes can be loaded?
The integer part of (container internal L ÷ box L) × the integer part of (internal W ÷ box W) × the integer part of (internal H ÷ box H) gives the base load quantity. This calculator adds interlocking loading that compares the box rotated lengthwise and crosswise, then automatically selects the arrangement that loads more.
Why is the maximum load CBM smaller than the container's usable capacity?
A container's usable capacity (20ft 28 · 40ft 58 · 40HC 68 CBM) is the volume when filled seamlessly, as with liquids or grain. Fixed-shape boxes leave leftover space along the edges when they do not divide evenly into the container's internal dimensions. For example, stacking 30cm boxes in a 40HC (269cm internal height) fits only 8 tiers (240cm), leaving 29cm empty. As a result, the 40HC maximum load for 30cm boxes is 2,240 = 60.48 CBM (89% of the 68 CBM usable). The closer the box dimensions are to the container's internal dimensions, the higher this space efficiency. The "Maximum load" field shows both the actual load CBM and the efficiency (%) relative to usable capacity.
Does the CBM calculator result give me a forwarding quote right away?
This tool is for pre-checking before a freight quote. Official quotes are calculated based on cargo type, origin, destination, Incoterms, and customs conditions, so you can receive a reply within 24 hours after requesting a quote from RUNIC.
* 1 CBM = 1 m³ = length (m) × width (m) × height (m). Box dimensions are entered in cm and converted internally to meters for calculation. The maximum load quantity is a theoretical value based on grid and interlocking loading, comparing the box rotated lengthwise and crosswise, and container utilization is based on entered quantity ÷ maximum load quantity. Actual loading may vary depending on weight distribution, cushioning materials, and loading method.
