Freight Density Calculator

What is freight density?

Freight density is a shipment’s weight divided by the space it occupies, measured in pounds per cubic foot. It is the primary input to NMFC freight class, the code that sets what an LTL carrier charges to move it.

LTL carriers sell trailer space, and for most commodities the price of that space starts with class. Dense freight earns more revenue per cubic foot of trailer, so it sits at a lower class number and a lower rate. Light, bulky freight fills a trailer without adding much weight, so it sits at a higher class.

The scale runs from class 50, at 50 pounds per cubic foot or more, down to class 400, under 1 pound per cubic foot. Eleven more bands sit between those two ends, and crossing a band edge changes the rate the carrier applies to the same goods.

How do you calculate freight density?

1. Measure length, width and height in inches, including the pallet, the wrap and any overhang. Round up.
2. Multiply L × W × H to get cubic inches.
3. Divide by 1,728 to get cubic feet.
4. Divide the total weight in pounds, pallet included, by the cubic feet. That is your density in pounds per cubic foot.

Worked through: a 48 by 40 inch pallet stacked to 48 inches occupies 92,160 cubic inches, or 53.33 cubic feet. At 500 pounds that is 9.38 pounds per cubic foot, which falls in the band from 8 up to 10, so the shipment classes at 100.

How do you measure a pallet for freight class?

Carriers measure what they pick up, not what is inside the box. Use the outer dimensions of the palletized or packaged unit and round each one up to the next inch.

• Include the pallet in the height, and its weight in the weight. 500 pounds of product on a 40 pound pallet is 540 pounds on the bill of lading, and leaving the pallet out understates the density that produced your class.
• Measure to the widest point, including stretch wrap, banding, corner boards and anything hanging over the pallet edge. Overhang adds cubic feet without adding weight, which pushes density down and class up.
• For a loose carton, measure the carton. For a cylinder, drum or an irregular shape, measure the rectangular space it occupies at its greatest dimensions, which is the space the carrier has to give it on the trailer.
• Density is calculated per handling unit. Where the shipping papers show only a total weight for all the handling units tendered, that total may be used instead, which is worth knowing before you split one pallet into two.

How do you lower your freight class?

On the density scale there is only one lever, and it is density itself. Anything that puts more weight into the same cubic feet, or the same weight into fewer, moves the shipment toward a lower class.

• Take void space out. Right-sized cartons, less dunnage and tighter case packs are the cheapest density you can buy.
• Stack taller rather than wider, where the commodity and the carrier allow it. Height adds cubic feet at the same rate as width, but a taller stack usually carries more weight per pallet position.
• Keep the load inside the pallet footprint. Overhang is the most common avoidable density loss on an LTL pallet.
• Consolidate. Two half-built pallets moving on the same lane almost always classify worse than one full one.
• Declare what you actually tendered. An understated class comes back as a reweigh, a corrected invoice and an inspection fee, which costs more than the class you were trying to avoid.

How your freight is packed and palletized is usually decided by whoever handles it, which is why this shows up in 3PL pricing long before it shows up on a carrier invoice.

Freight density vs dimensional weight

They answer the same question, that light and bulky freight should not ship at the price of its scale weight, and they answer it with different arithmetic. LTL uses density to pick a class, and the class sets the rate. Parcel uses dimensional weight: cubic inches divided by a DIM divisor, and the shipment bills on whichever is greater, the actual weight or the dimensional weight.

The divisors matter more than they look. A divisor of 139, the published figure for UPS and FedEx retail rates, is arithmetically the same as demanding about 12.4 pounds per cubic foot, because 1,728 divided by 139 is 12.43. Anything lighter than that per cubic foot bills on its dimensions instead of its weight. A 166 divisor, which appears in USPS retail pricing, works out to about 10.4 pounds per cubic foot.

So a pallet at 9.38 pounds per cubic foot classes at 100 on the LTL scale and would be billed on dimensions by a parcel carrier at either divisor. Density is the number underneath both systems; only the conversion changes.

What changed in the 2025 NMFC density scale?

On July 19, 2025 the National Motor Freight Classification moved a large share of its items off fixed, commodity-based classes and onto a single density scale of thirteen sub-provisions. That is the scale on this page, and it is why a density lookup now answers for far more LTL shipments than it used to.

Two things follow, and both are worth checking against whatever chart you were using before. The scale tops out at class 400: on these thirteen bands there is no class 500. And most charts still circulating show eleven tiers, which puts the same density one class too high almost everywhere below 35 pounds per cubic foot.

A separate instrument, the Commodity Classification Standards Board density guidelines, uses eighteen classes and different breakpoints, and that is where classes such as 500 and 77.5 belong. The two are not interchangeable, and splicing them is how a chart ends up returning a class no carrier will agree with.

Why does freight class matter for your 3PL?

What happens when the class is wrong

If the class on your bill of lading is lower than what the carrier measures at the dock, the shipment is reweighed or remeasured and the invoice is adjusted, usually with an inspection charge on top. The shipments this happens to are the ones sitting close to a band edge, which is why this calculator flags a density within 5 percent of a boundary and names the class you would land on instead.

Your density is built in the warehouse

Whoever packs, palletizes and wraps your freight decides its density before a carrier ever sees it. Carton selection, case pack, stack height, overhang and how readily orders are consolidated are all operational choices, and they set the class you pay on. That makes it a fair question to put to a provider before you sign: how do you build pallets for LTL, and what do you do when a shipment lands near a band edge?

Density is also why two quotes for the same goods can differ without either one being wrong. Reading them side by side gets easier once you know what drives each line item.