To determine freight class, you need to identify your shipment’s NMFC classification and evaluate its density, handling requirements, stowability, and liability.
Getting this right matters because freight class directly impacts how much you pay for less-than-truckload (LTL) shipping—and even small mistakes can lead to higher costs, reclassification fees, or shipment delays.
In LTL shipping, freight class is one of the biggest pricing drivers:
Estimating freight class accurately from the start helps you control spend, avoid billing surprises, and keep freight moving smoothly through the network.
Freight class is a standardized classification system established by the National Motor Freight Transportation Association (NMFTA). It groups commodities based on how difficult they are to transport, using a consistent set of criteria so carriers can price and handle freight appropriately.
In simple terms, freight class tells carriers:
How much space your shipment will take up
How easy it is to move
How much risk is involved in transporting it
LTL freight classes range from 50 to 500, with lower numbers representing freight that is denser, easier to handle, and less costly to ship. There are 18 total classes within this range, and each step up reflects added complexity, space usage, or risk.
Here’s a high-level breakdown to help frame how freight classes typically work:
Class 50-60: Extremely dense, durable freight that moves efficiently.
Class 65-85: Solid, stackable freight with moderate density.
Class 92.5-125: Freight with average density and some handling considerations.
Class 150-250: Lighter or more delicate items that are harder to stack or protect.
Class 300-400: Low-density freight that takes up more trailer space.
Class 500: Extremely low-density freight that is bulky relative to its weight.
As a general rule, freight that is compact, heavy for its size, and easy to stack falls into lower classes. Freight that is bulky, lightweight, fragile, or awkwardly shaped tends to move into higher classes (and higher costs).
The NMFTA assigns freight classes based on four primary characteristics. Understanding these factors makes it much easier to estimate freight class accurately and avoid surprises later.
Density measures how much weight your shipment has relative to the space it occupies. It is calculated as pounds per cubic foot and plays a major role in determining freight class.
To calculate density:
Cost Impact: Freight with higher density typically ships more efficiently and is assigned a lower class. Lower-density freight takes up more trailer space per pound, which increases costs and pushes it into higher classes.
Stowability refers to how easily your freight can be loaded alongside other shipments. This includes whether it can be stacked, how uniformly shaped it is, and whether it fits on standard pallets
Items that are oversized, oddly shaped, or restricted due to regulations (such as hazardous materials) are harder to load efficiently.
Cost Impact: Freight that disrupts trailer space or requires special placement generally moves into a higher freight class because it limits how carriers can optimize their loads.
Handling considers how easy—or difficult—it is for dock workers and drivers to move your shipment. Packaging quality, fragility, and the need for special equipment all factor in.
Cost Impact: Freight that requires extra care, specialized tools, or additional labor increases operational complexity. That added effort is reflected in a higher freight class.
Liability accounts for the risk associated with transporting your shipment. This includes the likelihood of damage, theft, spoilage, or the potential for your freight to damage other shipments.
Cost Impact: High-value, delicate, or high-risk freight is more costly to insure and manage. As risk increases, so does freight class—and ultimately, shipping cost.
If you’re wondering how to determine freight class accurately, following a clear process helps reduce guesswork and costly errors.
Use a certified scale to determine the total shipment weight. Be sure to include all packaging materials, pallets, and crates in the final number.
Measure the length, width, and height of the shipment in inches. If the freight is palletized, include the pallet dimensions. If multiple pieces are involved, measure the full footprint and height of the stacked load.
Using your weight and dimensions, calculate the shipment’s density. This step often determines whether your freight falls into one class or another, especially for NMFC items with density-based classifications.
Review whether your freight has:
These factors can influence final classification even if density alone suggests a lower class.
Start by finding the correct National Motor Freight Classification (NMFC) code for your product. Each NMFC code corresponds to a specific commodity description and associated freight class criteria.
NMFTA’s ClassIT+ database allows shippers to search for commodities using detailed product descriptions. The more specific your search terms, the more accurate your classification will be. Some NMFC codes assign different freight classes based on density, so precise measurements are critical.
While these steps provide a solid estimate, freight class determination isn’t always straightforward. Carriers may assess freight differently based on handling, liability, or packaging.
Working with experienced logistics professionals—like S-2’s freight strategists—helps validate your classification, reduce risk, and ensure consistency across shipments.
Freight class has a direct and measurable impact on LTL shipping costs. Carriers use it to determine pricing, space allocation, and handling procedures.
When freight is misclassified, several issues can arise:
Today, many LTL carriers use automated dimensioning systems, visioning technology, and precision scales. These tools quickly verify weight and dimensions, making discrepancies easier to detect. If your numbers don’t match, your shipment can be reclassified automatically—sometimes before it even leaves the dock.
Simply put, freight class accuracy leads to better cost control and a more predictable shipping experience.
S-2’s freight strategists bring deep expertise in freight classes and LTL shipping. We help shippers and freight forwarders validate freight characteristics, confirm accurate classifications, and avoid unexpected costs or overpaying.
If you have questions about how to determine freight class, need help reviewing an estimate, or want a trusted partner to support your LTL strategy, we’re here to help you get it right.
Reach out to S-2 to protect your budget, reduce risk, and keep your freight moving smoothly.