An NMFC number is a code assigned to every type of commodity shipped through less-than-truckload (LTL) freight carriers in the United States. It stands for National Motor Freight Classification number, and it tells carriers exactly what you’re shipping, how to handle it, and what freight class (and therefore what price tier) applies. Think of it as a product ID for the freight world: each commodity, from engine parts to canned food to furniture, gets its own item number in a master catalog maintained by the National Motor Freight Traffic Association (NMFTA).
How NMFC Numbers Work
The NMFTA maintains a massive classification database where thousands of commodities are each assigned a unique NMFC item number. That item number maps to a freight class ranging from 50 to 500. Class 50 is the cheapest to ship (dense, durable, easy-to-handle goods), while class 500 is the most expensive (light, fragile, or awkward items). When you book an LTL shipment, you list the NMFC number on your bill of lading so the carrier knows exactly what’s on the truck and what rate to charge.
The NMFC number and the freight class are related but not the same thing. The item number identifies the specific product. The freight class is the pricing category that number falls into. Two different products can share the same freight class but have completely different NMFC item numbers. Getting the item number right is what ensures the correct class, and the correct price, gets applied to your shipment.
Four Factors That Determine Classification
Every commodity’s freight class is based on four transportation characteristics that reflect how difficult and costly it is to move:
- Density: How much the item weighs relative to the space it takes up. A pallet of steel bolts is far denser than a pallet of pillows, so the bolts get a lower (cheaper) class.
- Handling: Some freight is straightforward for dock workers to move with a forklift or pallet jack. Other items, due to their size, weight, fragility, or hazardous nature, require special care. Unusual handling needs push the class higher.
- Stowability: This covers how easily the item fits inside a trailer alongside other freight. Items that can’t be stacked, that have odd shapes or protrusions, or that must be kept separate from hazardous materials are harder to stow and cost more to ship.
- Liability: This factor accounts for the risk of the item being damaged in transit, its potential to damage other freight nearby, whether it’s perishable, and whether it’s hazardous. Higher risk means a higher class.
For many common commodities, density is the dominant factor. But an item that’s easy to damage, difficult to stack, or classified as hazardous can land in a higher freight class even if it’s relatively dense.
Why the Right NMFC Number Matters
Using the correct NMFC item number on your bill of lading directly affects three things: what you pay, how smoothly the shipment moves, and whether you get hit with extra charges after delivery.
If you use the wrong number, the carrier may reclassify your shipment during transit or at delivery. That reclassification often comes with a higher freight class and a bigger invoice than you expected. The NMFTA warns that misclassified shipments lead to unexpected charges, delays, and disputes. These billing adjustments can show up weeks after pickup, forcing your team to resolve discrepancies, manage carrier disputes, and absorb administrative costs.
Beyond pricing, the NMFC number also communicates handling instructions. A correctly classified shipment tells the carrier whether the item needs special stacking, temperature considerations, or separation from certain materials. That translates to safer handling and fewer damage claims.
How to Look Up an NMFC Number
The NMFC database is not freely available online. It’s a proprietary classification system, and access requires a paid subscription through the NMFTA. The official lookup tool is called ClassIT+, which lets you search for the correct item number, calculate density, and confirm freight class before you ship. Each license is tied to a single user, so companies with multiple people classifying freight need multiple subscriptions.
If you don’t have direct access, there are a few practical alternatives. Your freight broker or third-party logistics provider (3PL) almost certainly has a subscription and can look up the number for you. Many LTL carriers also provide classification assistance or have commodity lookup tools on their websites, though these may not cover every item. When you’re getting a freight quote, the broker or carrier will typically ask for a product description, dimensions, and weight, then match it to the appropriate NMFC number.
Recent Changes to the System
The NMFTA rolled out significant updates to the NMFC system in 2025, with frequent revisions continuing throughout the year. These updates changed how certain commodities are classified, which means item numbers and freight classes that were accurate last year may no longer apply. If your business ships regularly and you’re relying on NMFC numbers you looked up months or years ago, it’s worth verifying them against the current database.
Outdated classifications can trigger the same problems as incorrect ones: unexpected charges, shipment delays from carrier inspections, and disputes between shippers and carriers. The NMFTA recommends that warehouse, logistics, and accounting teams all stay aware of classification changes to prevent costly mistakes. If you use a 3PL or broker, confirm that they’re working from the latest version of the database.
Where NMFC Numbers Appear
You’ll encounter NMFC numbers in several places during the LTL shipping process. The most important is the bill of lading, the document that travels with your freight and serves as the contract between you and the carrier. You’ll also see the number on freight quotes, carrier invoices, and claims paperwork. Some shippers include it on purchase orders and internal inventory systems to streamline the quoting process for future shipments.
If you’re shipping full truckloads (FTL) rather than LTL, NMFC numbers are generally not relevant. The classification system exists specifically for LTL shipping, where multiple shippers’ freight shares space on the same truck and carriers need a standardized way to price and handle each commodity.