Question 1

What is CBM in shipping and how do I calculate it?

Accepted Answer

CBM (Cubic Meter) is the standard volume unit in international freight. Multiply length × width × height in meters: a 100 × 50 × 50 cm carton = 0.25 m³. Use our CBM calculator for multi-package shipments and container utilization.

Question 2

What is dimensional (DIM) weight and how do carriers bill it?

Accepted Answer

DIM weight is volumetric weight: (L × W × H in³) ÷ divisor. FedEx/UPS use 139 for domestic ground and 166 for international (2026 rates). You are billed on whichever is greater — actual or DIM — so reducing box size saves freight cost.

Question 3

How many CBM fits in a 40ft container?

Accepted Answer

A standard 40ft container holds 67.7 CBM, a 40ft High Cube holds 76.4 CBM, and a 45ft High Cube holds 86.0 CBM. Target 80–95% utilization for the best cost-per-CBM economics.

Question 4

How is freight class determined?

Accepted Answer

NMFC freight class is set by density (weight ÷ volume in lbs/ft³). Class 50 is the cheapest (≥ 50 lbs/ft³) and Class 500 is the most expensive (< 1 lbs/ft³). Use density tier lookup to map weight + dimensions to the right class.

Question 5

How do I convert cubic meters to cubic feet?

Accepted Answer

1 m³ = 35.3147 ft³. Multiply CBM by 35.3147 to get cubic feet, or divide ft³ by 35.3147 to get m³. Most US carriers use ft³; most international forwarders use m³.

Question 6

What is the difference between actual and billable weight?

Accepted Answer

Actual weight is what the package weighs on a scale. Billable weight is the greater of actual or dimensional weight. Carriers bill on billable weight to discourage shipping light, bulky packages cheaply.

Question 7

How do I optimize container loading for cost savings?

Accepted Answer

Calculate total CBM, aim for 80–95% container fill, group cartons by density, and use the Quick Conversion strip to compare 20ft vs 40ft container costs. Lower fill = wasted freight rate.

Question 8

What is the NMFC and who maintains it?

Accepted Answer

The National Motor Freight Classification (NMFC) is published by the National Motor Freight Traffic Association (NMFTA). It defines 18 freight classes based on density, stowability, handling, and liability — the foundation of LTL pricing.

Question 9

Why does dimensional weight matter for e-commerce?

Accepted Answer

A 1-lb pillow in a 20×20×20 in box has actual weight 1 lb but DIM weight ~58 lbs (20³ ÷ 139). E-commerce sellers minimize DIM by right-sizing packaging, which can cut shipping cost by 30–50%.

Question 10

How accurate are these shipping calculators?

Accepted Answer

Mathematically exact for the formulas shown. For carrier billing, always verify with the carrier rate card — fuel surcharges, accessorials, and zone-based pricing add on top of the base freight calculation our tools provide.

Container	Internal CBM	Internal ft³	Max payload (kg)
20ft Standard	33.2	1,172	28,180
40ft Standard	67.7	2,390	28,800
40ft High Cube	76.4	2,697	28,560
45ft High Cube	86.0	3,037	27,600

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