What Do Freight Classes and NMFC Codes Really Mean?
Picture this: You’re ready to ship a pallet of goods across the country. You’ve nailed down the packaging, picked your carrier, and scheduled a pickup. Then—bam—you’re hit with a surprise fee. Why? Because of something called a “freight class.”
If you’ve ever found yourself scratching your head over freight classes or NMFC codes, you’re not alone. These terms might sound like jargon, but understanding them is key to avoiding extra fees, damaged goods, and delivery delays.
Let’s break it all down—minus the confusing logistics lingo.
What Is a Freight Class?
In the U.S., the National Motor Freight Traffic Association (NMFTA) developed a standardized classification system to make shipping easier and more consistent. That’s where freight classes come in.
There are 18 freight classes, ranging from Class 50 (least expensive) to Class 500 (most expensive). Each class is based on four key characteristics:
- Density: How much space the item takes up versus how much it weighs.
- Stowability: How easily it fits in with other freight.
- Handling: The ease or difficulty of loading and unloading.
- Liability: The risk of theft, damage, or spoilage.
Higher freight classes typically mean higher shipping costs because the items are harder to transport or take up more room.
Example: A compact box of metal bolts is dense and easy to stack—likely a Class 50. A large, lightweight foam display? That could jump to Class 300 or higher.
What Are NMFC Codes?
Each product you ship is assigned an NMFC (National Motor Freight Classification) code. This numerical code acts like a universal identifier that tells carriers exactly what’s being shipped.
Think of it as the “SKU of shipping.” It eliminates guesswork and helps ensure accurate pricing and compliance.
An NMFC code is tied to a specific freight class. So if you know your product’s NMFC code, you can find out its freight class—and vice versa.
Why It Matters:
- Carriers use NMFC codes to quote prices.
- Incorrect codes can lead to reclassification fees or shipment delays.
- Accurate codes protect against disputes and claims.
For the most up-to-date NMFC codes, check the NMFTA website.
Why Getting It Right Saves You Money (and Stress)
Here’s the kicker: Misclassifying freight is a common reason for surprise charges. If the carrier inspects your freight and finds a mismatch, you could be re-billed at a higher rate.
Some shippers even overpay as a “safe guess.” But consistently using accurate freight classes and NMFC codes can result in significant savings over time.
Tips to Avoid Freight Class Headaches:
- Use a Freight Class Calculator: Many 3PLs and LTL carriers offer online tools.
- Weigh and Measure Accurately: Density is a big factor.
- Consult Your Carrier or Broker: They often have databases of common NMFC codes.
- Use Consistent Packaging: Standardized pallets help avoid reclassification.
How Density Affects Freight Class (And Your Wallet)
Let’s say you’re shipping foam cushions. They’re lightweight but take up a lot of space. This reduces their density—and raises their freight class.
On the flip side, steel parts are heavy and compact, meaning high density and lower freight class.
To calculate density:
Density = Weight (lbs) / Volume (cubic feet)
Where:
- Volume = Length × Width × Height (in inches) ÷ 1,728
Understanding this formula can help you pack more efficiently and potentially lower your freight class.
Common NMFC Codes by Product Type
Here’s a quick snapshot of typical NMFC codes and their corresponding freight classes:
| Product Type | NMFC Code | Freight Class |
|---|---|---|
| Wooden Furniture | 79300 | 100-250 |
| Metal Tools | 133300 | 70-85 |
| Plastic Containers | 156600 | 125-250 |
| Tires | 192400 | 110-150 |
| Clothing/Apparel | 49940 | 100-150 |
Note: Always double-check codes based on specific product size and packaging.
Regulatory and Legal Considerations
The NMFTA regularly updates the NMFC codes. Keeping current ensures compliance with legal regulations and industry standards.
For businesses, getting these classifications wrong doesn’t just risk fees—it can also affect your shipping liability and insurance claims.
According to FreightWaves, disputes over misclassified freight are one of the top issues in LTL (Less Than Truckload) shipping claims today.
Freight Class and NMFC Code FAQs
1. Can two items have the same NMFC code but different freight classes?
Yes. Factors like packaging, density, and stowability can shift the assigned class even within the same product type.
2. How often do NMFC codes change?
The NMFTA reviews and updates codes multiple times a year. It’s smart to check quarterly if you ship regularly.
3. Is it illegal to guess a freight class?
Not illegal—but risky. If you’re consistently guessing, you could be overpaying or opening yourself to disputes.
4. What’s the easiest way to find the correct NMFC code?
Use a freight broker or shipping software that accesses the NMFC database. Or refer to the NMFTA’s Classification Tool.
5. Do all shipping carriers use NMFC codes?
Most LTL carriers in the U.S. use NMFC codes. However, parcel carriers like UPS or FedEx may use different methods for classification.
Final Thoughts: Mastering the Freight Maze
Freight classes and NMFC codes might not be the most glamorous part of logistics—but they are absolutely essential.
Getting them right helps you save money, avoid reclassification charges, and keep your shipments running smoothly. Whether you’re a small business owner or a logistics manager, a little extra attention to these details goes a long way.
Need help finding your freight class or NMFC code? Don’t hesitate to consult a licensed broker or check out NMFTA’s online tools. It’s better to ask questions now than pay penalties later.
Ready to ship smarter? Let accuracy be your competitive advantage.