How do I calculate freight density?

Freight Density = Total Weight (lbs) / Total Volume (ft³). To find volume: multiply length x width x height in inches, then divide by 1,728 (12 x 12 x 12). For multiple cartons, calculate total volume and total weight, then divide weight by volume.

What freight class is my shipment?

Freight class is determined by density. Denser shipments get lower classes (cheaper). Class 50 is for items over 50 lb/ft³, while Class 500 is for items under 1 lb/ft³. Our calculator automatically determines the correct NMFC freight class based on your density.

Freight Density Calculator — Determine LTL Freight Class

Freight Density Calculator

Calculate freight density and instantly find the NMFC freight class for your LTL shipment. Enter dimensions and weight to get your class.

Shipment Details

Dimensions in

Weight in

Length

Width

Height

Total Weight

Number of Pieces

What is Freight Density?

Freight density is the weight of a shipment per cubic foot, measured in lb/ft³. It is the single most important factor in determining your LTL (Less Than Truckload) freight class. Denser shipments occupy less trailer space relative to their weight, which means a lower freight class and lower shipping rates.

Freight Density Formula

Density = Total Weight (lbs) ÷ Total Volume (ft³)

To calculate volume in cubic feet: Length (in) × Width (in) × Height (in) ÷ 1,728

For multiple identical cartons, multiply the single carton volume by the quantity to get total volume, then divide total weight by total volume.

NMFC Freight Classes by Density

The National Motor Freight Classification (NMFC) system assigns one of 18 freight classes based on density:

Class 50: 50+ lb/ft³ — Very dense, heavy items (machine parts, steel)
Class 65–100: 9–35 lb/ft³ — Standard freight (furniture, electronics)
Class 125–200: 4–8 lb/ft³ — Lighter items (clothing, packaged food)
Class 250–500: <4 lb/ft³ — Bulky, lightweight items (ping pong balls, insulation)

Lower classes mean lower per-pound shipping rates. Accurately calculating density helps you avoid reclassification fees from carriers.

Why Freight Class Matters

LTL carriers assign freight class to determine pricing. If you declare an incorrect class, the carrier may reclassify your shipment and charge a higher rate plus a reclassification fee. Using our density calculator ensures you quote the correct class upfront, saving time and money.