Freight Class Demystified: How It Impacts Your LTL Shipping Costs
When an LTL freight quote comes back higher than expected, freight class may be one of the reasons.
Freight class plays a major role in how less-than-truckload shipments are rated, quoted, and billed. Yet for many shippers, it remains one of the most confusing parts of the LTL shipping process.
Two pallets can have the same weight and travel the same distance but receive very different rates. The difference may come down to how much trailer space each shipment occupies, how easily it can be handled, and the risk involved in transporting it.
Understanding freight class can help you produce more accurate shipping quotes, avoid reclassification fees, and make better packaging decisions before your freight ever reaches the dock.
What Is Freight Class?
Freight class is a standardized system used to categorize commodities moving through the less-than-truckload freight network.
The National Motor Freight Classification, commonly called the NMFC, assigns freight to one of 18 classes ranging from Class 50 to Class 500. Lower classes generally represent freight that is dense, durable, easy to handle, and relatively efficient to transport. Higher classes are typically assigned to freight that takes up more space, requires special handling, or carries greater risk.
In simple terms, freight class helps carriers evaluate how difficult and expensive a shipment will be to move through their network.
LTL carriers do not simply load a shipment once and drive it directly to the destination. Freight may move through several terminals, trailers, and distribution points. Each shipment must fit efficiently with freight from other customers.
Freight class gives carriers a consistent way to account for those operational differences.
What Determines an LTL Freight Class?
Freight classification is based on four primary transportation characteristics:
1. Density
Density measures how much a shipment weighs compared to the amount of space it occupies.
A compact pallet of metal components may weigh thousands of pounds while using very little trailer space. A pallet of lightweight plastic products may occupy the same amount of space while weighing only a few hundred pounds.
The heavier and more compact shipment will generally have a lower freight class. The lighter, bulkier shipment will often have a higher class.
Density has become increasingly important under the updated NMFC framework. Many commodities are now classified using density-based scales rather than relying only on product descriptions. Major NMFC changes that took effect on July 19, 2025 expanded the use of density-based classification and introduced a 13-tier density scale for applicable commodities.
2. Stowability
Stowability refers to how easily the freight can be positioned alongside other shipments inside a trailer.
Freight may be more difficult to stow if it:
Has an unusual shape
Cannot be stacked
Contains hazardous materials
Requires separation from other products
Extends beyond the dimensions of the pallet
Uses trailer space inefficiently
A standard, square pallet that can support freight stacked above it is generally easier for a carrier to manage than an irregularly shaped item that prevents nearby space from being used.
3. Handling
Handling evaluates how easily the shipment can be moved through terminals and onto or off trailers.
Freight that can be moved with a standard forklift or pallet jack is generally easier to handle. Long, fragile, top-heavy, loose, or unusually shaped products may require additional time, labor, or specialized equipment.
The more difficult a shipment is to handle, the greater the possibility of delay, damage, or injury. That added operational burden can contribute to a higher freight class.
4. Liability
Liability considers the risk associated with transporting the product.
Carriers may evaluate factors such as:
Product value
Fragility
Susceptibility to theft
Risk of damage
Potential to damage other freight
Perishability
Hazardous characteristics
A shipment containing inexpensive, durable machine parts presents a different level of risk than a shipment containing fragile electronics or high-value equipment.
Density, stowability, handling, and liability work together to determine how a commodity should be classified.
How Freight Class Affects LTL Shipping Costs
Freight class is one of several factors used to calculate an LTL rate.
Carriers also consider:
Shipment weight
Origin and destination
Distance traveled
Number of pallets
Dimensions
Fuel costs
Required accessorial services
Available carrier capacity
Minimum charges
Contracted discounts
Freight class helps establish the base rate associated with the shipment. In general, a higher class results in a higher rate because the freight is considered less efficient, more difficult, or riskier to transport.
For example, imagine two shipments that each weigh 500 pounds.
The first shipment contains dense metal hardware secured to a compact pallet. The second contains lightweight molded products packed in large cartons.
Although the shipments weigh the same, the second shipment occupies more trailer space. It may therefore receive a higher freight class and cost more to ship.
That is why weight alone does not determine an LTL shipping rate.
How to Calculate Freight Density
For commodities classified primarily by density, you will need three pieces of information:
The shipment’s total weight
Its length, width, and height
The total cubic volume
First, calculate cubic feet:
Length × Width × Height ÷ 1,728 = Cubic Feet
Then calculate density:
Total Weight ÷ Cubic Feet = Pounds Per Cubic Foot
Consider a pallet that measures 48 inches long, 40 inches wide, and 48 inches high and weighs 800 pounds.
The calculation would be:
48 × 40 × 48 = 92,160 cubic inches
92,160 ÷ 1,728 = 53.33 cubic feet
800 ÷ 53.33 = approximately 15 pounds per cubic foot
That density can then be matched to the appropriate NMFC density scale, provided the commodity’s NMFC item uses density-based classification.
Not every product is classified strictly by density, so shippers should verify the applicable NMFC item number and description rather than assuming density alone determines the class.
NMFTA recommends using accurate shipment weights and dimensions rather than estimates. Its ClassIT+ platform is the official digital tool for looking up NMFC items, calculating density, and confirming freight class.
What Happens When the Freight Class Is Wrong?
Incorrect freight classification can create problems long after a shipment has been picked up.
Carriers frequently inspect, weigh, and measure freight as it moves through their networks. If the carrier determines that the listed class does not match the actual commodity, density, dimensions, or packaging, it may reclassify the shipment.
This can result in:
Additional freight charges
Reweigh or inspection fees
Billing adjustments
Delayed invoice approval
Disputes between the shipper and carrier
Reduced accuracy in future freight budgets
Delays in processing freight claims
In some cases, the difference between the quoted class and the inspected class can significantly increase the final bill.
For example, a shipment quoted at Class 70 may be inspected and reassigned to Class 125. The revised rate may be much higher than the amount originally approved.
Accurate freight information protects both the shipper and the carrier. It also helps a logistics provider compare rates using consistent shipment data.
Freight Class vs. NMFC Number
Freight class and NMFC number are related, but they are not the same thing.
An NMFC number identifies a specific commodity or category of commodities within the National Motor Freight Classification.
The freight class represents the rating category assigned to that commodity.
Some NMFC items have one fixed class. Others include multiple possible classes based on shipment density, packaging, or other product characteristics.
A generic product description such as “parts,” “equipment,” or “materials” is rarely enough to determine the correct classification. The exact commodity, construction material, packaging method, and shipment density may all matter.
Using a detailed product description is one of the most important steps in identifying the correct NMFC number and freight class.
Common Freight Classification Mistakes
Even experienced shipping departments can run into classification problems. Some of the most common mistakes include:
Estimating Pallet Dimensions
A pallet listed as 48 inches high may actually measure 54 inches after cartons, wrapping, and protective materials are added.
Those extra inches increase the shipment’s cubic volume and reduce its calculated density.
Ignoring Packaging
Freight dimensions should include the complete handling unit, not just the product itself.
Pallets, crates, cartons, corner boards, overhang, and protective packaging must be included in the final measurements.
Reusing an Old Freight Class
NMFC items and classifications can change. A class that was correct for a product several years ago may no longer be accurate.
The NMFTA made broad classification changes in 2025, and its official tools continue to update as NMFC provisions change.
Using a Broad Commodity Description
“Plastic goods” or “machinery parts” may describe thousands of products with very different transportation characteristics.
Specific descriptions make classification more accurate and make it easier to defend the class if a carrier questions it.
Measuring Only One Pallet
When a shipment contains pallets of different sizes or weights, each handling unit should be measured and documented accurately.
Assuming every pallet is identical can distort the shipment’s total density.
Confusing Freight Class With Shipping Price
Freight class affects pricing, but it is not the entire rate.
A lower class does not automatically guarantee the lowest total cost. Distance, lane conditions, accessorials, carrier availability, and service requirements can all change the final quote.
How to Reduce Freight Class Problems
Shippers can improve classification accuracy by creating a repeatable process before requesting an LTL quote.
Measure Freight After It Is Packaged
Record the final length, width, and height of the complete pallet or crate.
Always measure the widest, longest, and tallest points, including any product or packaging that extends beyond the pallet.
Use Accurate Scales
Small weight errors may have a major effect when a shipment falls near the boundary between density classes.
Verified shipping scales provide more reliable data than production estimates or product specifications.
Keep Product Information Organized
Maintain a record of frequently shipped commodities, including:
Detailed product description
NMFC number
Freight class
Typical dimensions
Typical weight
Packaging type
Density calculation
This creates consistency across shipping locations and employees.
Improve Packaging Efficiency
Reducing unused space can increase density and potentially improve freight classification for density-based commodities.
Better packaging can also help reduce damage, improve stackability, and make freight easier for carriers to handle.
However, shippers should never compromise product protection simply to reduce dimensions.
Review Classification Regularly
NMFC rules are not static. Product listings, item numbers, density provisions, and classification rules can change.
Regular reviews can help prevent a previously correct shipment profile from becoming outdated.
Work With an Experienced Logistics Provider
A logistics provider can help review shipment characteristics, identify possible classification concerns, compare carriers, and ensure quote information is complete before the freight is tendered.
That support is especially valuable for new products, unusual freight, multi-pallet shipments, and commodities that fall under density-based classifications.
Frequently Asked Questions About Freight Class
Does a higher freight class always cost more?
Generally, higher freight classes produce higher base rates because they indicate freight that is less dense, more difficult to handle, harder to stow, or more likely to create liability.
However, the final rate also depends on the lane, shipment weight, carrier, contract pricing, accessorials, and current market capacity.
Can the same product have different freight classes?
Yes. Some NMFC commodities have multiple classes based on density, packaging, or other shipment characteristics.
The same product may be assigned a different class if one shipment is packed more efficiently than another.
Who determines the freight class?
The NMFC provides the classification standards. The shipper is responsible for describing and classifying the freight accurately when preparing the shipment.
Carriers may inspect and reclassify freight if the submitted information does not match the shipment.
Is freight class used for full truckload shipping?
Freight class is primarily associated with LTL shipping.
Full truckload rates are generally based more heavily on the truck, lane, mileage, equipment type, market conditions, and required service. Freight class may still appear in documentation, but it typically does not drive the rate in the same way it does for LTL freight.
Can packaging lower an LTL shipping cost?
It can.
More compact, stackable, and secure packaging may improve density, reduce handling difficulty, lower damage risk, and allow carriers to use trailer space more efficiently.
Whether packaging changes the actual freight class depends on the applicable NMFC item.
Take the Guesswork Out of LTL Shipping
Freight class is more than a number entered on a bill of lading. It reflects how a shipment uses trailer space, moves through terminals, and affects a carrier’s cost and risk.
Getting it right can help your business:
Receive more accurate LTL quotes
Reduce reclassification charges
Improve freight budgeting
Avoid billing disputes
Select appropriate carriers
Build a more consistent shipping process
Welcome Logistics helps shippers navigate the details behind LTL transportation, from freight classification and carrier selection to shipment coordination and delivery.
When your freight information is accurate from the beginning, your pricing, planning, and shipping performance become more predictable.
Contact Welcome Logistics to discuss your next LTL shipment and find a transportation solution built around your freight, timeline, and business requirements.
