NMFC Freight Classes Explained: 18 Classes, Codes, and Costs

The National Motor Freight Classification sorts every commodity shipped by Less-than-Truckload (LTL) carriers into one of 18 NMFC freight classes, numbered from 50 to 500. The class is set mainly by density, with handling, stowability, and liability also factored in, and it is the single biggest driver of what you pay. Lower class numbers mean denser, easier freight and cheaper rates; higher numbers mean lighter or riskier freight and sharply higher rates. The system is maintained by the National Motor Freight Traffic Association (NMFTA) so that carriers and shippers describe goods the same way across the industry.¹

The Four Factors Behind Every Class

Every commodity is evaluated against four transportation characteristics: density, handling, stowability, and liability.¹ Density does most of the work, and the NMFTA has been steadily moving the whole system toward density as the primary metric. The other three still matter when a commodity presents unusual problems.

Density

Density is pounds per cubic foot. Multiply your shipment’s length, width, and height in inches, divide by 1,728 to convert to cubic feet, then divide the total weight by that cubic footage.² A 500-pound pallet measuring 48 × 40 × 36 inches works out to about 40 cubic feet and a density of 12.5 pounds per cubic foot, which drops it into a specific class range. Carriers favor dense freight because it earns more revenue per trailer without eating floor space.

Handling

Handling is how hard the shipment is to load, move, and unload. Palletized freight that works with a standard forklift sits in lower classes. Fragile, oversized, or awkwardly shaped items push upward, and hazardous materials that need bracing or protective measures land in more expensive tiers because they demand extra labor at every touchpoint.

Stowability

Stowability is how well your freight fits next to other cargo. Clean rectangular pallets stack and nest; irregular shapes, protrusions, and “top load only” markings waste trailer space the carrier could otherwise fill with paying freight. When goods can’t be stowed efficiently, the class goes up.

Liability

Liability is the carrier’s financial risk during transit: the value of the commodity, the odds of theft, and the chance of damage from vibration, temperature swings, or contamination. Perishables and high-value electronics both climb the ladder because a claim on them costs the carrier more than a claim on concrete blocks.

The 18 NMFC Freight Classes and Their Density Ranges

Each class corresponds to a density range measured in pounds per cubic foot (pcf). Lower class numbers mean denser freight and lower rates; higher numbers mean bulkier or riskier freight and higher rates.

Class 50: 50 pcf or more (for example, raw steel or bags of flour)³
Class 55: 35 to 50 pcf²
Class 60: 30 to 35 pcf²
Class 65: 22.5 to 30 pcf
Class 70: 15 to 22.5 pcf
Class 77.5: 13.5 to 15 pcf
Class 85: 12 to 13.5 pcf
Class 92.5: 10.5 to 12 pcf
Class 100: 9 to 10.5 pcf
Class 110: 8 to 9 pcf
Class 125: 7 to 8 pcf
Class 150: 6 to 7 pcf
Class 175: 5 to 6 pcf
Class 200: 4 to 5 pcf
Class 250: 3 to 4 pcf
Class 300: 2 to 3 pcf
Class 400: 1 to 2 pcf
Class 500: less than 1 pcf

Class 500 freight includes items like bags of ping pong balls, certain antiques, and extremely low-density packaging materials. Class 50 freight is a carrier’s ideal load: heavy, compact, hard to damage.

What Each Class Step Costs You

Freight class is not a minor line item. The difference between the right class and the wrong one can swing a shipment’s cost by 30% or more. LTL carriers build their tariffs around class, so a higher class means a higher per-hundredweight rate before any negotiated discounts apply.

As a rough benchmark, Class 50 freight typically costs about half of what Class 70 costs at the same weight. By Class 200, you’re paying three to four times the Class 70 rate. Class 500 runs about ten times the Class 70 baseline. Multipliers vary by carrier and contract, but the pattern holds: every step up the ladder costs more, and the jumps get bigger near the top.

Some carriers also apply a density minimum charge (sometimes called a cubic minimum charge) when a shipment is especially bulky for its weight. If density drops below a carrier-specific threshold, the carrier may recalculate charges based on the cubic space consumed rather than the class alone. This tends to hit shipments around 2.5 pcf or lower, though each carrier sets its own trigger.

The Shift Toward Density-Based Classification

The NMFTA has been overhauling the system to make density the dominant factor. Historically, each commodity carried its own classification based on a blend of all four factors, which produced inconsistencies and frequent disputes. Under changes rolled out through Docket 2025-1, commodities that don’t present unusual handling, stowability, or liability concerns are classified purely by density using a standardized 13-tier subprovision scale.²

Under the old system, two commodities with identical density could land in different classes because one had a legacy description that weighted handling more heavily. The density-based model removes that inconsistency. Items that do have notable handling, stowability, or liability issues keep tailored classifications, but even those often use density breaks within their specific code.²

Many individual commodity descriptions have been canceled and folded into broader density-based items. The total number of distinct NMFC item numbers has been reduced. If you haven’t checked your NMFC codes recently, the specific item number you’ve been using may no longer exist, which means your shipments can get reclassified in transit.

How to Find the Right NMFC Code

The NMFC code is a five- or six-digit number assigned to a specific commodity, and it’s different from the freight class itself. The code identifies what the product is; the code’s subprovisions then determine the class. A single commodity code often contains multiple subprovisions, each assigning a different class based on density, so two pallets of the same product can fall into different classes if one is packed more compactly.²

To find your code you need precise numbers: exact weight in pounds and every dimension in inches, including any overhang from pallets or protective packaging. Material composition matters too. A wooden chair and a plastic chair may fall under different NMFC items or different subprovisions within the same item. If your exact product isn’t listed, the NMFC provides “Not Otherwise Indexed” (NOI) categories that group similar commodities into a general entry.

The NMFC database is not publicly available. Lookups require a paid subscription through the NMFTA’s ClassIT+ platform, which starts at $299 per year for NMFTA members and $345 for non-members on a single-user web plan. API access for integration with a transportation management system starts at $2,760 per year.⁴ The platform offers keyword search, filtering by effective date, and real-time updates when classifications change.⁵

If you ship infrequently, a freight broker or carrier can usually look up codes for you. But relying entirely on a carrier to classify your freight means trusting the party that benefits from a higher classification to assign it accurately. At minimum, know your shipment’s exact density before you call.

When Carriers Reclassify Your Shipment

Carriers routinely inspect LTL shipments in transit. If they weigh your freight and measure its dimensions and the numbers don’t match what you declared on the Bill of Lading, they’ll reclassify it and bill you the difference, plus an adjustment fee. The combined hit on a single shipment can be substantial.

The most common trigger is understating dimensions. Shippers measure the product and forget to include pallet overhang, shrink wrap bulge, or protective packaging that extends past the pallet edge. The carrier’s dimensioner catches every inch. The second most common trigger is using an outdated NMFC code that’s been canceled or consolidated in a recent docket update.

To avoid reclassification, measure every shipment at its widest, tallest, and longest points including all packaging. Weigh it on a calibrated scale. Confirm the NMFC code is still active. Document everything with photos before the shipment leaves your dock. If a carrier reclassifies your freight and you believe the adjustment is wrong, your dispute is with the carrier. The NMFTA maintains the classification standards but does not adjudicate individual billing disputes between shippers and carriers.⁶

1
National Motor Freight Traffic Association. National Motor Freight Classification
2
National Motor Freight Traffic Association. 2025 NMFC Changes Frequently Asked Questions
3
National Motor Freight Traffic Association. FCDC Density Guidelines
4
National Motor Freight Traffic Association. ClassIT+ Pricing
5
National Motor Freight Traffic Association. ClassIT+
6
National Motor Freight Traffic Association. Freight Classification Development Council Procedures