*Note: This is an estimate based on density. Final classification may vary based on stowability, handling, and liability as defined by the NMFC.
How Freight Class is Determined
In the world of Less-Than-Truckload (LTL) shipping, freight class is a standardized method used to classify commodities. Established by the National Motor Freight Traffic Association (NMFTA), these classes ensure that shippers and carriers have a uniform pricing structure. There are 18 different freight classes, ranging from Class 50 (the least expensive) to Class 500 (the most expensive).
The Role of Density in Freight Shipping
While four factors influence freight class (Density, Stowability, Handling, and Liability), density is the most critical metric for most shipments. Density is calculated by dividing the total weight of the shipment by its total volume in cubic feet.
Density Formula:
Density = Total Weight (lbs) / (Length" x Width" x Height" / 1728)
Freight Class Density Table
Generally, higher density results in a lower freight class and lower shipping costs. Use the table below to see how density typically maps to NMFC classes:
Density (lbs per cubic foot)
Typical Freight Class
Over 50
Class 50
35 to 50
Class 55
22.5 to 30
Class 65
15 to 22.5
Class 70
10.5 to 12
Class 92.5
8 to 9
Class 110
6 to 7
Class 150
3 to 4
Class 250
Less than 1
Class 500
Example Calculation
Suppose you are shipping a standard pallet of machinery:
Dimensions: 48″ L x 40″ W x 48″ H
Weight: 800 lbs
Step 1: Calculate Cubic Inches (48 x 40 x 48 = 92,160)