What is CBM?
CBM stands for cubic meters. It is a metric unit of volume that describes how much space your consignment takes. If you need to work in imperial units, use the following conversion:
1 CBM = 1 m³ = 35.3147 cu ft
You can switch the calculator above between metric (cm / kg) and imperial (in / lbs) modes at any time.
How to Calculate CBM?
To calculate CBM, follow these simple steps:
- Measure the length, width, and height of your package.
- Make sure all values are in the same unit (cm for metric, inches for imperial).
- Multiply all three values together using the CBM formula:
CBM = Length × Width × Height (in metres)
Once you know the CBM of a single carton, the total volume of your consignment is:
Total Volume = CBM × Quantity
Total Weight vs. Volumetric Weight
When you enter the weight of a single carton, the calculator automatically returns two additional values:
- Total weight — the actual combined weight of all cartons (weight per carton × quantity).
-
Volumetric weight — an artificial measure of how much space the shipment occupies.
It is calculated as:
Volumetric weight (kg) = L (cm) × W (cm) × H (cm) × quantity ÷ shipping factor
The default shipping factor is 5 000 cm³/kg for metric and 139 in³/lbs for imperial, but it can vary by carrier — you can change it directly in the form.
Many carriers (FedEx, UPS, DHL, and others) charge whichever is higher — the total weight or the volumetric weight. This is called the Weight or Measurement (W/M) Rule. The calculator highlights the chargeable weight so you know exactly what to expect.
How to Use the Shipping Cube Calculator — an Example
- Set the unit system to Metric.
- Enter the dimensions of one shipping box: 50 cm × 80 cm × 60 cm.
- Enter the weight of one carton: 35 kg.
- Set the quantity to 20 cartons.
- Choose 40′ Standard as the container type.
- Click Calculate CBM.
The calculator will return:
- CBM per carton: 0.2400 m³
- Total volume: 4.8 m³
- Total weight: 700 kg
- Volumetric weight: 960 kg (higher → chargeable weight)
- Cartons per 40′ Standard container: ~282
Note: the number of cartons that fit in a container is an approximation. Actual figures may be lower due to the physical arrangement of boxes inside the container.
Container Types in the Cubic Meter Calculator
The calculator supports four standard dry-cargo container sizes:
| Container | Internal Volume |
|---|---|
| 20′ Standard | 33.2 m³ |
| 40′ Standard | 67.7 m³ |
| 40′ High Cube | 76.4 m³ |
| 45′ High Cube | 86.1 m³ |
Choose No container (LCL / partial) if your shipment will go as Less than Container Load — in that case the container fit result is not shown.
How to Calculate CBM When Your Package Is Irregularly Shaped?
For irregularly shaped items, always use the bounding box — the smallest imaginary rectangular box that completely encloses the item. Measure the maximum length, maximum width, and maximum height of the item and use those values in the calculator.
Estimating Shipping Cost
Enable the optional Estimate shipping cost section in the form to calculate a cost estimate. Enter your carrier's rate either per m³ (CBM rate) or per unit of chargeable weight (kg or lbs), then select the billing currency — the calculator supports 20 world currencies including USD, EUR, GBP, CNY, JPY, RUB, INR, BRL, and more.
The estimated cost is calculated as: Rate × Total Volume (if billing per m³) or Rate × Chargeable Weight (if billing per weight).
Why the CBM Calculation for Sea Shipment Matters
Sea freight is almost always priced per CBM (or per tonne, whichever is higher). Knowing the exact volume of your cargo lets you:
- Choose the right container size to avoid paying for unused space.
- Consolidate shipments efficiently for LCL bookings.
- Negotiate better rates with freight forwarders.
- Prepare accurate shipping documentation.
FAQs
- What is the formula for CBM?
- CBM = Length (m) × Width (m) × Height (m). In centimetres: divide each dimension by 100 first.
- What is the shipping factor (divisor)?
- It is a carrier-specific constant used to convert a box's physical dimensions into a comparable weight. Common values are 5 000 cm³/kg (metric) and 139 in³/lbs (imperial), but FedEx, UPS, and DHL may use different figures — check your carrier's tariff.
- What does W/M rule mean?
- Weight or Measurement — the carrier charges whichever is higher, the actual (total) weight or the volumetric weight. This prevents shippers from sending large, light packages at the same price as heavy ones.
- How many boxes fit in a 20-foot container?
- It depends entirely on the box dimensions. Enter your box size in the calculator above and select the 20′ Standard (33.2 m³) container to find out instantly.
- Can I use inches and lbs?
- Yes. Switch the unit system to Imperial in the form — the calculator will accept dimensions in inches, weight in lbs, and automatically use the imperial shipping factor (139 in³/lbs). The result is still shown in m³ with a cu ft equivalent alongside.