Importing goods from China to the USA is the backbone of thousands of businesses, from Amazon FBA sellers to dropshippers. However, one acronym causes more confusion than any other: CBM.
If you don’t calculate your CBM (Cubic Meters) correctly before booking your shipment, you could end up paying for a full container when you only needed half, or worse—having your cargo rejected at the port.
In this guide, we’ll explain exactly how to calculate CBM for China-US shipments and why it determines your final landed cost.
What is CBM in International Trade?
CBM stands for Cubic Meter. It is a measurement of volume.
- 1 CBM is a cube that is 1 meter wide, 1 meter long, and 1 meter high.
When shipping from China, your freight forwarder will quote you a price based on Revenue Tons. In Sea Freight (LCL), this is almost always based on CBM.
Why CBM Matters for US Importers
Most US importers start with LCL (Less than Container Load). This means your goods share a container with other people’s goods.
- You pay specifically for the space your boxes occupy.
- If you miscalculate your CBM, your freight forwarder will re-measure at the warehouse (often at a higher rate).
How to Calculate CBM for Your Shipment
The formula is simple, but you must be precise.
Formula: Length (m) × Width (m) × Height (m) = CBM
Practical Example: Shipping Cartons of Phone Cases
Let’s say you are importing 50 cartons of iPhone cases from Shenzhen to Los Angeles.
- Carton Dimensions: 50cm x 40cm x 30cm
- Quantity: 50 Cartons
Step 1: Convert to Meters
- 50cm = 0.5m
- 40cm = 0.4m
- 30cm = 0.3m
Step 2: Calculate Volume of One Carton
- 0.5 * 0.4 * 0.3 = 0.06 CBM
Step 3: Calculate Total Volume
- 0.06 CBM * 50 Cartons = 3.00 CBM
Tip: Don’t want to do the math? Use our Free CBM Calculator at the top of the homepage.
CBM Limits: When to Switch from LCL to FCL?
One of the biggest money-saving secrets in logistics is knowing when to stop using LCL and book a full container (FCL), even if you can’t fill it.
The “Break-Even” Point: Usually, around 13 to 15 CBM, it becomes cheaper to book a generic 20ft Container than to pay for LCL.
- LCL: You pay per CBM + high destination fees at the US port.
- FCL: You pay a flat rate for the container + lower flat fees.
If your calculator shows your shipment is over 15 CBM, ask your forwarder for an FCL quote immediately.
3 Common Mistakes When Calculating CBM
- Trusting the Supplier Blindly: Alibaba suppliers often guess the CBM. Always ask for the “Packing List” with exact dimensions and calculate it yourself.
- Ignoring Pallets: If you ask your supplier to put boxes on pallets (for easier unloading at Amazon FBA warehouses), you must calculate the volume of the pallet, not just the boxes. A standard pallet adds significant volume.
- Mixing Units: Make sure you aren’t multiplying centimeters by inches. Always convert to meters first.