Freight Class Calculator

Estimate your shipment's NMFC freight class from its dimensions and weight, using the standard density formula (weight divided by cubic feet).

Quick Facts

Model
NMFC density-based classification
Density (PCF) = total weight / total cubic feet; density is the primary driver of the 18 standard freight classes (50 to 500).

Your Results

Calculated
Density
-
Pounds per cubic foot (PCF)
Total volume
-
Cubic feet, all pieces
Total weight
-
Pounds, all pieces
Estimated freight class
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NMFC density-based class

Ready

Enter dimensions, weight, and piece count, then press Calculate.

About the Freight Class Calculator

Freight class is a standardized rating used by less-than-truckload (LTL) carriers in the United States to price shipments under the National Motor Freight Classification (NMFC) system, maintained by the National Motor Freight Traffic Association. There are 18 classes, running from 50 (very dense, cheap to ship per pound) up to 500 (very light and bulky, expensive to ship per pound). This calculator applies the density-based method that carriers and shippers use for the vast majority of general commodities.

The density formula

Density drives freight class for most shipments. The calculation has two steps:

  • Cubic feet = (length in inches x width in inches x height in inches) / 1728, multiplied by the number of identical pieces in the shipment.
  • Density (PCF) = total weight in pounds / total cubic feet. PCF stands for pounds per cubic foot.

The resulting density is then matched against the standard NMFC density table below to read off the freight class.

Standard NMFC density table

  • Under 1 PCF: Class 400
  • 1 to under 2 PCF: Class 300
  • 2 to under 4 PCF: Class 250
  • 4 to under 6 PCF: Class 175
  • 6 to under 8 PCF: Class 125
  • 8 to under 10 PCF: Class 100
  • 10 to under 12 PCF: Class 92.5
  • 12 to under 15 PCF: Class 85
  • 15 to under 22.5 PCF: Class 70
  • 22.5 to under 30 PCF: Class 65
  • 30 PCF or greater: Class 60

Why class matters and its limits

A lower class number generally means a lower shipping rate per hundredweight, because dense freight makes efficient use of trailer space. A higher class (light, bulky freight like foam or empty containers) costs more per pound because it takes up trailer volume without adding much weight. This calculator gives the standard density-based estimate. The full NMFC classification also considers stowability, handling difficulty, and liability (damage or theft risk) for specific named commodities, which can shift certain items to a different official class regardless of density — always confirm the assigned NMFC item number with your carrier for billing purposes.

Frequently Asked Questions

How is freight class calculated from dimensions and weight?
Freight class under the NMFC system is primarily driven by density. First find total cubic feet: (length x width x height, all in inches) / 1728, multiplied by the number of identical pieces. Then divide total weight in pounds by total cubic feet to get density in pounds per cubic foot (PCF). That density is matched against the standard NMFC density table to get a class from 400 (very low density) down to 50-60 (very high density).
What is the NMFC density table used to assign class?
The commonly used density brackets are: under 1 PCF = class 400, 1 to under 2 = class 300, 2 to under 4 = class 250, 4 to under 6 = class 175, 6 to under 8 = class 125, 8 to under 10 = class 100, 10 to under 12 = class 92.5, 12 to under 15 = class 85, 15 to under 22.5 = class 70, 22.5 to under 30 = class 65, and 30 PCF or greater = class 60. Lower density freight gets a higher (more expensive) class.
Does density alone always set the final freight class?
Density is the primary factor and the one this calculator uses, but the full NMFC also weighs stowability, handling difficulty, and liability for many commodity items. This tool gives the standard density-based estimate; freight with an assigned NMFC code may carry a different official class from the carrier's tariff, so confirm with your carrier before billing.

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