How Freight Density Affects LTL Class
Why density in pounds per cubic foot now drives most LTL freight classes, and how to calculate it before you ship.
Less-than-truckload (LTL) freight is grouped into classes that describe how easy a shipment is to haul. Since July 2025 the NMFTA has moved most commodities to a density-based model, and revises it periodically. In practice this means the single most useful number you can know about a pallet is its density in pounds per cubic foot (PCF). Density is permanent physics, it does not change with the market, so calculating it first tells you which class band you are likely to land in before you ever speak to a carrier.
How to calculate freight density
Density is weight divided by the volume the shipment occupies, measured to its outer dimensions including the pallet and any overhang:
Density (PCF) = weight in lb / volume in ft3
To get cubic feet from inches, multiply length x width x height and divide by 1,728 (the number of cubic inches in a cubic foot). Use the full footprint and the loaded height, not the carton size, because the carrier rates the space the unit actually blocks on the trailer.
A worked example
Take the default on our freight density calculator: a pallet 48 x 40 x 48 in weighing 400 lb.
- Volume: 48 x 40 x 48 = 92,160 in3, divided by 1,728 = 53.33 ft3
- Density: 400 / 53.33 = 7.5 lb/ft3
A density of about 7.5 PCF maps to an estimated class of 125. Add or remove weight and the class moves: the same pallet at 8 PCF would estimate to class 110, while a light, bulky load near 4 PCF would estimate to class 200. To check whether the pallet is over its rated capacity at that weight, the pallet weight calculator is the companion tool.
How density maps to estimated class
The table below is an advisory density-to-class guide. Higher density means a denser, cheaper-to-handle load and a lower class number.
| Density (lb/ft3) | Estimated class |
|---|---|
| 50 or more | 50 |
| 30 | 60 |
| 22.5 | 65 |
| 15 | 70 |
| 12 | 85 |
| 9 | 100 |
| 7 | 125 |
| 6 | 150 |
| 4 | 200 |
| 2 | 300 |
| 1 | 400 |
| less than 1 | 500 |
The class shown by any density tool is an estimate from density only. The NMFTA changed NMFC to its density-based model in July 2025 and revises it periodically, and some commodities still carry handling, stowability or liability adjustments. Always verify the current classification with your carrier or the NMFTA before booking, and never trust a static per-commodity NMFC lookup table, because those go stale.
Why density is worth calculating first
There are three practical reasons to run the density number before you ship:
- It is stable. Unlike a quoted class, density is geometry and weight. Once you measure the pallet, the figure does not drift.
- It tells you where you can improve. If a load is light and bulky, tightening the stack or reducing height raises density and can move it into a lower-numbered band.
- It catches re-class risk early. If your measured density sits near a tier boundary, a small change in actual weight or dimensions can push the load across into the next class, so it is worth knowing before the freight is on a dock.
Density governs palletised LTL the way the divisor governs parcel dimensional weight: both turn the space a shipment occupies into the figure a carrier rates on. For parcels under a courier label, the dimensional weight calculator is the right starting point instead.