NMFC Codes vs. Freight Class: Understand the Difference

Every less-than-truckload (LTL) shipment has to be classified before it moves. That classification helps carriers understand what you're shipping and plays a role in determining your rate. But getting it right means understanding two terms that are closely connected: NMFC codes and freight class.

An NMFC code identifies the commodity you're shipping, while freight class is one factor carriers use to determine your LTL shipping rate. And with recent changes to the National Motor Freight Classification (NMFC), density now plays a bigger role for many commodities. That means the class you've used in the past may not be the right one today.

Fortunately, freight classification doesn't have to be complicated. We'll break down how NMFC codes and freight class work together, what's changed and how to classify your LTL freight with confidence.

What are NMFC codes and why do they matter to freight class?

The National Motor Freight Classification is a standard published by the National Motor Freight Traffic Association (NMFTA) for classifying commodities moving through the LTL freight system.

Within the NMFC, commodities are assigned an NMFC item number, commonly called an NMFC code or NMFC number. Think of it as the starting point for determining how your freight should be classified.

Here's the key difference:

• NMFC code: Identifies the commodity you're shipping and the classification rules that apply to it.
• Freight class: Places freight into a numbered classification used in determining LTL shipping rates.
  NMFC freight classes range from 50 to 500. But the correct class isn't determined by the product name alone. Depending on the NMFC item, density may determine the class. Other transportation characteristics can also affect classification.

That's why relying on an old NMFC number or simply reusing a previous freight class can cause problems. If your shipment information doesn't match the applicable classification, the carrier may reclassify the freight and adjust the charges.

For current NMFC information, shippers can use NMFTA's ClassIT+ platform. If you're still getting familiar with LTL classification, our Common Freight Terms & Definitions can help you understand the terminology, while our Less-than-Truckload Services page provides a broader look at LTL shipping.

How Freight Class Is Determined: Density, Stowability, Handling and Liability

The NMFC considers four transportation characteristics when establishing freight classification. Following the 2025 NMFC changes, density became the primary factor for many commodities that don't present unusual handling, stowability or liability concerns.

Factor What It Means

Factor	What It Means
Density	How much the shipment weighs relative to the space it occupies
Stowability	How easily the freight can be loaded with other shipments
Handling	Whether the freight requires special care or presents handling challenges
Liability	The freight's susceptibility to damage, theft or other forms of loss

For commodities classified using the standard density scale, greater density generally corresponds to a lower freight class. That makes getting your weight and dimensions right especially important.

But not every commodity is classified solely by density. Start by identifying the correct NMFC item so you know which classification rules apply to your freight.

Want to check your numbers? Use our Freight Density Calculator to calculate shipment density before you ship.

How to Look Up the Right NMFC Number for Your Shipment

Finding the right NMFC number starts with knowing exactly what you're shipping. A broad product description may not give you enough information to identify the correct item.

Here's how to narrow it down:

1. Identify the commodity. Start with a specific description of the product you're shipping.
2. Find the applicable NMFC item. Use ClassIT+ to search current NMFC information and find the item that best matches your commodity.
3. Review the classification rules. Determine whether the item uses the standard density scale or has other requirements.
4. Calculate density when required. Use the shipment's actual weight and dimensions as it will be tendered to the carrier.
5. Check the shipment details. Make sure the description and packaging match the NMFC provisions you're using.

Classification requirements can change. Even if you ship the same products regularly, it's worth checking that the NMFC number and class you have on file are still current.

Need help navigating your LTL shipment? Our team can help you evaluate your freight needs and get a freight shipping quote.

NMFC Freight Class Chart: Understanding the Density Scale

NMFC freight classes range from 50 to 500. For commodities subject to the current standard 13-subprovision density scale, density maps to Classes 50 through 400.

Here's how the scale works:

Density (lbs./ft³)	Freight Class
Less than 1	400
1 but less than 2	300
2 but less than 4	250
4 but less than 6	175
6 but less than 8	125
8 but less than 10	100
10 but less than 12	92.5
12 but less than 15	85
15 but less than 22.5	70
22.5 but less than 30	65
30 but less than 35	60
35 but less than 50	55
50 or greater	50

This chart applies to NMFC items that use the standard 13-subprovision density scale. It isn't a universal freight class chart for every commodity.

That's an important distinction. Calculating your density doesn't automatically tell you your freight class.

First find the correct NMFC code, then use the classification provisions for that item to determine the class.

The 2025-2026 NMFC changes: What's different?

Freight classification changed significantly beginning in 2025. NMFTA expanded the use of a standardized density-based approach while continuing to account for commodities with other transportation characteristics.

Here's a quick look at the major updates:

NMFC Update	Effective Date	What Changed
2025-1	July 19, 2025	Expanded the standard density scale from 11 to 13 subprovisions and moved more than 2,000 items toward full-density classification
2025-2	December 6, 2025	Continued the NMFC modernization with additional item changes and updates to classification provisions
2026-1	May 23, 2026	Introduced another round of approved NMFC changes affecting specific items, rules and classification provisions

What does that mean for your business? The freight class you've used for years may no longer apply.
If you haven't reviewed your commonly shipped commodities since the NMFC changes took effect, now is a good time to do it. Check current NMFC codes and make sure the information used in your shipping systems and documentation is up to date.

Understanding why freight gets reclassified can help you prevent unexpected changes to your shipping costs.

Avoiding Reclassification Fees and NMFC Disputes

You booked the shipment. You have your rate. Then the final charges don't match what you expected.
One possible reason is freight reclassification. If a carrier determines that the commodity, weight, dimensions or freight class differs from the information provided when the shipment was rated, it may reclassify the freight and adjust the charges.

You can reduce that risk by building a few good habits into your shipping process:

• Weigh and measure the complete shipment. Account for the pallet and packaging, including anything extending beyond the pallet.
• Use an accurate commodity description. Make sure it reflects what's actually being shipped.
• Verify your NMFC information. Don't automatically reuse an NMFC number or freight class from an older shipment.
• Keep supporting documentation. Good shipment records can help if you need to review or dispute a reclassification.

And pay attention to patterns. If similar shipments keep getting reclassified, there's probably something worth investigating. An outdated NMFC item or incorrect shipment measurements could be creating the same problem again and again.

Using a Density Calculator to Confirm Your Class

If your NMFC item is classified by density, accurate measurements are essential. Fortunately, the math itself is simple:

Total shipment weight ÷ total cubic feet = density in pounds per cubic foot

Measure the shipment as it will be tendered to the carrier. That means accounting for the complete handling unit, not just the product inside it.

Once you know the density, use the classification provisions for your NMFC item to determine the applicable freight class. This gives you a much stronger starting point for an accurate LTL quote.

Our Freight Density Calculator can help you quickly calculate density before you ship. When you're ready to put that information to work, get a freight shipping quote from Worldwide Express.

FAQ: NMFC Codes and Freight Class