Freight Density

What it means

NMFTA, the group that publishes the National Motor Freight Classification (NMFC), gives the method. Multiply the greatest straight-line length, width and height in inches, including all projections, as tendered to the carrier. Divide the total by 1,728 cubic inches, which is one cubic foot. Then divide the weight of the handling unit as tendered by the cubic feet.^[1]

NMFTA lists density as one of four transportation characteristics that set a commodity's class, along with handling, stowability and liability. It describes density as how heavy the freight is relative to the space it takes up, and says the denser and easier to move, the lower the class and the lower the cost.^[2] To turn a density into a class, use the freight class calculator.

Measure the whole handling unit

Density is figured on the handling unit as it goes to the dock, not on the product inside it. NMFTA's method uses the greatest dimensions including all projections.^[1] One carrier rules tariff spells this out: cube is based on the extreme length, width and depth, including containers, pallets, platforms, racks, reels, skids or projecting portions.^[4]

• Include the pallet. A standard pallet adds height and some weight. Measure from the floor to the highest point.
• Include overhang. If cartons stick out past the pallet edge, use the outside edge of the cartons, not the pallet size.
• Use the widest point. A leaning or bulging stack is measured at its widest and tallest point.
• Write it down. Measure to the inch and put the dimensions and weight on the bill of lading.
• Weigh it loaded. Use the gross weight of the unit with pallet, wrap and packaging.

The same tariff says each line on the bill of lading is figured separately, a single package under one cubic foot is rated as one cubic foot, and cubic feet are length times width times depth in inches divided by 1,728.^[4] A neat, square pallet build with no overhang is the simplest way to keep cube low. When a load arrives leaning or oversized, repalletizing can bring it back to a cleaner footprint.

Why density matters to LTL pricing

LTL carriers sell space on a shared trailer. Light, bulky freight fills the trailer before it reaches the weight limit, so it costs the carrier more per pound to move. That is why low density usually means a higher freight class, and as the class increases, the rate per hundred pounds increases.^[5]

Density also shows up in carrier rules. One rules tariff says that when a commodity is classed by density and the density is not on the bill of lading, the carrier first bills at the class for the lowest density in that NMFC item. The charges are adjusted if the shipper later proves a higher actual density.^[4] The same tariff applies a special minimum charge to shipments over 750 cubic feet with an average density under 4 pcf.^[4]

If the carrier remeasures and finds a lower density than you declared, the class and the bill can change. See why an LTL shipment gets reclassified and how LTL freight is priced for the rest of the invoice.

The NMFC move toward density-based classes

The NMFC has been shifting more commodity items to classes set by density. NMFTA's Disposition Bulletin 1371 for Docket 2025-1 records the changes the Freight Classification Development Council acted on at its March 3, 2025 public meeting. The resulting amendments were scheduled for a supplement issued May 10, 2025, with an effective date of July 19, 2025.^[3]

Many of the amended items now use what the bulletin calls the FCDC's standard 13-subprovision density scale. On that scale the classes run from 400 for freight under 1 pcf down to 50 for freight at 50 pcf or more.^[3] Not every commodity uses this scale, and some items keep their own provisions. Check the current NMFC item for your product, or let the freight class calculator do the math.

The practical result is simple. For more products, the class now depends on how you pack and measure, not only on what the product is. That makes accurate dimensions on the bill of lading more important than before.

Why it matters

Density is the number a carrier checks when it remeasures freight on the dock. Getting it right before pickup keeps the class you quoted and avoids a corrected invoice. Small packing changes, like removing overhang or squaring up a stack, can move a shipment across a density line. RapidShips runs a warehouse in East Brunswick, NJ, and is not a carrier, so the carrier's tariff and the current NMFC decide the class that is billed.

Example

Illustrative only, not a real shipment or quote. A pallet of cartons weighs 380 lb with the pallet. It measures 48 x 40 in. and stands 52 in. tall from the floor. 48 x 40 x 52 = 99,840 cubic inches. 99,840 / 1,728 = 57.78 cubic feet. 380 / 57.78 = 6.58 pcf.

Now say the cartons overhang the pallet by 2 inches on every side, so the outside size is 52 x 44 x 52 in. That is 118,976 cubic inches, or 68.85 cubic feet. 380 / 68.85 = 5.52 pcf. Same freight, same weight, about 16 percent less density. If the item used the standard 13-subprovision scale, 6.58 pcf would fall in the 6 to under 8 pcf band (class 125) and 5.52 pcf in the 4 to under 6 pcf band (class 175).^[3]

Common mistakes

• Measuring the carton, not the pallet. The handling unit includes the pallet and anything that sticks out.^[1]
• Leaving density off the bill of lading. Some tariffs then bill at the lowest density in the NMFC item until you prove otherwise.^[4]
• Forgetting the 1,728 step. Weight divided by cubic inches gives a tiny number that means nothing for class.
• Using a nominal pallet size. A 48 x 40 pallet with 2 inches of overhang on each side is measured at the carton edges.

Frequently asked questions