About the Freight Class Calculator
This freight class calculator measures the density of a less-than-truckload (LTL) shipment — its weight per cubic foot — and maps it to an estimated National Motor Freight Classification (NMFC) class using the density guidelines published by the National Motor Freight Traffic Association (NMFTA). Enter the length, width and height of each handling unit (pallet, crate or skid including the pallet itself), the weight of each unit and how many there are.
It is useful for shippers, e-commerce sellers and freight brokers who need a class before requesting an LTL quote, and for checking a carrier re-class or inspection correction. Dense freight earns a low class (50 is the densest and cheapest), while light, bulky freight climbs toward class 400 or 500 and costs more per hundredweight.
Density is only one of four classification factors — stowability, handling and liability also matter — and many commodities have their own NMFC item with a fixed class or a commodity-specific density scale. The NMFC is amended through periodic dockets, so treat the result as an estimate based on the NMFTA density guidelines and confirm the current item number for your commodity before you put a class on the bill of lading.
With the default inputs, the estimated freight class is 100. Change any value above to recalculate instantly.
How to use the freight class calculator
- 1Choose inches/pounds or centimetres/kilograms.
- 2Measure the length, width and height of one handling unit, including the pallet.
- 3Enter the weight of one unit with pallet and packaging.
- 4Enter how many identical handling units are in the shipment.
- 5Read the density and estimated class, then confirm the NMFC item for your commodity.
Formula and method
Volume per handling unit is length × width × height in inches divided by 1,728 (cubic inches per cubic foot); metric dimensions are converted by dividing cubic centimetres by 28,316.85. Multiply by the number of units, then divide the total weight in pounds (kilograms × 2.20462) by the total cubic feet to get density.
The density is matched to the NMFTA Freight Classification Development Council density guidelines: at least 50 lb/ft³ is class 50, 35 to under 50 is class 55, and so on down to less than 1 lb/ft³ for class 500. Measure the outermost dimensions including the pallet and any overhang, because carriers bill on the space the freight actually occupies.
- L, W, H
- Outside length, width and height of each handling unit
- ft³
- Cubic feet of the whole shipment
- density
- Pounds per cubic foot (pcf)
Worked examples
Standard 48×40×48 in pallet weighing 500 lb
48 × 40 × 48 = 92,160 cubic inches, or 53.33 ft³. 500 lb ÷ 53.33 ft³ = 9.38 lb/ft³, which is in the 9 to under 10.5 band — class 100.
Three pallets of dense machine parts
Each pallet is 48 × 40 × 36 ÷ 1,728 = 40 ft³, so three are 120 ft³ weighing 4,200 lb. Density is exactly 35 lb/ft³, the minimum for class 55.
Metric pallet: 120 × 80 × 150 cm at 180 kg
120 × 80 × 150 = 1,440,000 cm³ ÷ 28,316.85 = 50.85 ft³. 180 kg is 396.8 lb, so density is about 7.8 lb/ft³ — class 125 (7 to under 8 lb/ft³).
Frequently asked questions
How is freight class determined?+
The NMFC assigns classes from 50 to 500 based on four transportation characteristics: density, stowability, handling and liability. For most general freight, density is the main driver, and the NMFTA density guidelines map pounds per cubic foot to a class.
How do I calculate freight density?+
Multiply length × width × height in inches, divide by 1,728 to get cubic feet, then divide the total weight in pounds by the cubic feet. A 48×40×48 in pallet weighing 500 lb is 53.33 ft³ and 9.38 lb/ft³.
Does a lower freight class cost less?+
Yes. LTL rates are quoted per hundredweight by class, and class 50 freight is the cheapest per pound while class 500 is the most expensive, because light bulky freight takes up more trailer space for its weight.
Should I include the pallet in the measurements?+
Yes. Measure the outermost dimensions of the handling unit including the pallet, any overhang and the highest point, and weigh the unit with its pallet and packaging. Carriers measure the same way when they inspect and re-class freight.
Why did my carrier re-class my shipment?+
Carriers inspect and measure freight with dimensioners. If the measured density, or the commodity’s NMFC item, gives a different class than the bill of lading, they correct it and bill the difference. Accurate dimensions and the right item number prevent this.
Is the density class always the right class?+
No. Many commodities have a specific NMFC item with a fixed class or their own density sub-provisions. Use this estimate to quote, but look up the item for your product (for example via NMFTA ClassIT) before shipping.