CBM and Freight Volume Guide

What is CBM?

CBM stands for cubic metres — the standard unit of volume used in international freight and logistics. One CBM equals the volume of a cube that is 1 metre long, 1 metre wide and 1 metre high. In freight, CBM is the basis for LCL (less-than-container-load) sea freight pricing, warehouse storage charges, and container utilisation calculations.

Why volume matters for freight pricing

Sea freight (LCL)

LCL sea freight is priced per CBM (or per 1,000 kg, whichever is greater — known as the “revenue ton”). If your cargo is light relative to its volume (common for furniture, textiles, plastic goods), you pay on volume. If it is dense (metal parts, chemicals), you pay on weight. Understanding your CBM tells you which billing basis applies and lets you compare quotes accurately.

Air freight

Air freight uses volumetric weight (also called dimensional weight) rather than CBM directly. The IATA standard formula is: L × W × H (cm) ÷ 6,000 = volumetric weight in kg. You are charged the higher of actual weight and volumetric weight. Bulky, lightweight goods are penalised because they take up aircraft space without contributing proportional weight revenue.

Warehouse storage

Third-party logistics (3PL) warehouses often charge per pallet position, per square metre of floor space, or per CBM of storage volume. Knowing your total CBM lets you estimate monthly storage cost and compare warehouse quotes.

Container planning

A standard 20ft container has approximately 33 CBM of internal capacity; a 40ft standard has approximately 67 CBM; a 40ft high-cube has approximately 76 CBM. Knowing your shipment’s total CBM tells you whether you need an FCL (full container load) and which container size to book — or whether LCL is more economical.

The relationship between CBM, freight cost and landed cost

Freight cost is one of the largest components of landed cost for imported goods — often 8%–20% of the product value for sea freight and 20%–50% for air freight. Because freight cost is driven by volume (for sea) or volumetric weight (for air), understanding and optimising your CBM directly reduces your landed cost per unit.

Practical ways to reduce effective CBM include: negotiating smaller carton dimensions with your supplier, increasing packing density (more units per carton), flat-packing where possible, and consolidating multiple SKUs into shared cartons.

Worked example

Common mistakes to avoid

• Using inner carton dimensions instead of outer — freight carriers measure the outer dimensions of each package. Interior dimensions understate the space your cargo actually occupies.
• Forgetting that LCL has minimum charges — most LCL carriers have a minimum charge (often 1 CBM). If your shipment is 0.3 CBM, you still pay the 1 CBM minimum.
• Ignoring the weight/volume comparison — always calculate both total weight (in tonnes) and total CBM. You will be charged on whichever is higher (the “revenue ton” or “freight ton” principle).
• Not accounting for pallet overhang — if goods are palletised, the pallet footprint and height determine the billable volume, not just the carton dimensions.
• Forgetting to include packaging in measurements — stretch wrap, corner protectors and pallet collars all add to the outer dimensions.

How the calculators help

The CBM Calculator computes total shipment volume from carton dimensions and quantities. The Container Loading Calculator tells you how many cartons fit in a 20ft or 40ft container. The Pallet Calculator works out cartons per pallet for warehouse and road freight planning. And the Landed Cost Calculator turns your freight cost into a per-unit landed cost figure for pricing decisions.