What is Freight Class? Complete NMFC Classification Guide for LTL Shipping
What Is Freight Class? The Complete Guide to NMFC Classification (2025)
Freight class is a standardized classification system used in Less-Than-Truckload (LTL) shipping to categorize commodities based on their transportability characteristics. Established and maintained by the National Motor Freight Traffic Association (NMFTA) through its publication, the National Motor Freight Classification (NMFC), freight classes range from Class 50 — the least expensive and easiest to transport — to Class 500 — the most expensive and most difficult to transport.
Every commodity shipped via LTL freight in the United States and Canada is assigned a freight class that directly determines the base shipping rate. Understanding how freight class works is essential whether you are shipping a single pallet through an LTL carrier or managing a complex supply chain with both full truckload (FTL) and regional trucking moves.
This guide covers every aspect of freight class — from the four classification factors and all 18 classes to NMFC code examples, the 2025 NMFTA density-based pricing transition, and how modern platforms auto-classify your shipments to prevent costly reclassification fees.
What Is the NMFTA and the NMFC?
The National Motor Freight Traffic Association (NMFTA) is a non-profit membership organization based in Alexandria, Virginia. Founded in 1954, it represents motor carriers operating in interstate, intrastate, and foreign commerce. Its primary function is to publish and maintain the National Motor Freight Classification (NMFC) — the industry-standard tariff that assigns a freight class to virtually every type of commercial commodity transported by truck in North America.
The NMFC is updated continuously. The NMFTA issues NMFC supplements throughout the year, adding new items, reclassifying existing commodities, and adjusting density thresholds as shipping practices evolve. As of 2025, the NMFC contains over 18,000 individual commodity descriptions, each with a specific NMFC item number and assigned class.
Why the NMFC Exists
Before the NMFC, individual carriers published hundreds of competing tariffs, making rate comparison nearly impossible. The NMFC created a uniform system so that a shipper in Texas and a carrier in Ohio could agree on a single classification for a pallet of automotive parts without consulting dozens of separate rate sheets. Today, virtually every LTL carrier in the United States uses NMFC classes as the foundation for their pricing.
The Four Factors That Determine Freight Class
The NMFC assigns every commodity a freight class based on four transportability characteristics. Each factor reflects a real cost that carriers incur when moving that type of freight.
1. Density
Density is the most heavily weighted factor in modern freight classification. It measures weight per cubic foot of space occupied. High-density freight — like steel plates or bottled water — is compact, stable, and easy to load efficiently. Low-density freight — like inflatable mattresses or foam packaging — consumes far more trailer space relative to its weight, reducing the carrier’s revenue per trip.
The density-to-class relationship is inverse: higher density = lower class number = lower rate. A shipment with a density above 50 lbs/cf falls into Class 50, the cheapest class. A shipment with a density below 1 lb/cf may fall into Class 500, the most expensive.
2. Stowability
Stowability measures how easily a commodity can be loaded alongside other freight in a trailer without wasting space or creating load conflicts. Items that are irregularly shaped, oversized, or cannot be stacked due to fragility receive a higher (more expensive) class. For example, a crated grandfather clock occupies far more trailer space than its weight suggests because other cargo cannot be stacked on top of it.
Hazardous materials that must be segregated from other freight also receive elevated classes due to poor stowability. Explosives (NMFC Class 70+ depending on type), certain flammable liquids, and corrosive materials all carry stowability surcharges embedded in their assigned class.
3. Handling
Handling reflects the special care, equipment, or labor required to move a commodity safely. Freight that requires two-person handling, specialized lift equipment, or extra padding during transit receives a higher class to compensate carriers for the additional cost. Examples include:
- Live plants or perishables requiring climate-controlled handling
- Machinery with protruding parts that can damage adjacent freight
- Medical equipment requiring white-glove delivery
- Fragile glass or ceramic items shipped without crating
4. Liability
Liability accounts for the value per pound of the commodity and its susceptibility to damage, theft, or spontaneous combustion. High-value freight — such as electronics, jewelry, or fine art — is assigned a higher freight class because carriers assume greater financial exposure if the shipment is damaged or lost. Similarly, commodities with a known theft risk (consumer electronics, pharmaceuticals) or that can self-ignite carry elevated liability factors that push their class upward.
How to Calculate Freight Density
Density is calculated using a simple formula, but accurate measurement is critical — even a small error in dimensions can shift your shipment into a higher freight class and trigger reclassification fees.
The Density Formula
Density (lbs/cf) = Weight (lbs) ÷ Volume (cubic feet)
To calculate volume in cubic feet from inch measurements:
Volume (cf) = [Length (in) × Width (in) × Height (in)] ÷ 1,728
The divisor 1,728 converts cubic inches to cubic feet (12³ = 1,728).
Step-by-Step Density Calculation Examples
Example 1 — Standard Pallet of Auto Parts
- Dimensions: 48″ L × 40″ W × 48″ H
- Weight: 650 lbs
- Volume: (48 × 40 × 48) ÷ 1,728 = 92,160 ÷ 1,728 = 53.33 cf
- Density: 650 ÷ 53.33 = 12.19 lbs/cf → Class 85
Example 2 — Boxed Electronics on a Pallet
- Dimensions: 48″ L × 40″ W × 60″ H
- Weight: 480 lbs
- Volume: (48 × 40 × 60) ÷ 1,728 = 115,200 ÷ 1,728 = 66.67 cf
- Density: 480 ÷ 66.67 = 7.2 lbs/cf → Class 125
Example 3 — Lightweight Furniture (Sofa)
- Dimensions: 96″ L × 42″ W × 38″ H
- Weight: 120 lbs
- Volume: (96 × 42 × 38) ÷ 1,728 = 153,216 ÷ 1,728 = 88.67 cf
- Density: 120 ÷ 88.67 = 1.35 lbs/cf → Class 300
Important Measurement Rules
- Always measure the longest, widest, and tallest point of the shipment, including packaging and pallet
- For irregularly shaped items, measure the smallest box that would fully contain the item
- When measuring palletized freight, include pallet height (typically 5.5″ for a standard wooden pallet)
- For multiple pieces on one shipment, calculate total weight divided by total cubic footage
All 18 Freight Classes: Complete Table with Density Ranges and Examples
| Class | Density Range (lbs/cf) | Typical Commodities | Example NMFC Items |
|---|---|---|---|
| 50 | 50+ lbs/cf | Sand, gravel, bricks, cement blocks, steel ingots, hardwood lumber | NMFC 100490 (Cement), NMFC 151260 (Stone) |
| 55 | 35–50 lbs/cf | Hardwood flooring, bottled beverages, automotive batteries, flour in bags | NMFC 62150 (Beverages, non-alcoholic) |
| 60 | 30–35 lbs/cf | Car parts (crated), steel cables, cast iron cookware, machine weights | NMFC 36640 (Auto parts, NOI) |
| 65 | 22.5–30 lbs/cf | Car accessories, motorcycles (boxed), books, tile | NMFC 24060 (Books, printed) |
| 70 | 15–22.5 lbs/cf | Auto engines, food items in boxes, bathroom vanities, steel wire | NMFC 20220 (Automobile engines) |
| 77.5 | 13.5–15 lbs/cf | Tires (mounted), refrigeration equipment parts, power tools | NMFC 155540 (Tires, pneumatic) |
| 85 | 12–13.5 lbs/cf | Crated machinery, cast iron stoves, truck parts, transmissions | NMFC 113560 (Machinery, NOI) |
| 92.5 | 10.5–12 lbs/cf | Computers (boxed), monitors, printers, small home appliances | NMFC 58750 (Computers, boxed) |
| 100 | 9–10.5 lbs/cf | Refrigerators, wine (boxed), cabinets, boat parts | NMFC 46840 (Refrigerators) |
| 110 | 8–9 lbs/cf | Cabinets (kitchen), microwaves, office chairs, display cases | NMFC 100240 (Chairs, office) — Class 125 unboxed |
| 125 | 6–8 lbs/cf | Small household appliances, LCD TVs (boxed), clothing, table saws | NMFC 100240 (Chairs, office), NMFC 53120 (Clothing) |
| 150 | 4–6 lbs/cf | Couches, auto sheet metal, barbecue grills, metal filing cabinets | NMFC 87700 (Furniture, NOI) |
| 175 | 3–4 lbs/cf | Clothing on hangers, stuffed animals, large flat-screen TVs (unboxed) | NMFC 53122 (Clothing, on hangers) |
| 200 | 2–3 lbs/cf | Aluminum tables, sheet metal (unpackaged), mattresses, wood furniture | NMFC 10020 (Aluminum, sheets) |
| 250 | 1–2 lbs/cf | Plasma TVs, bamboo furniture, large stuffed animals, balloon bouquets | NMFC 97800 (Plasma displays) |
| 300 | 0.75–1 lbs/cf | Wood cabinets (unassembled), wicker furniture, model boats | NMFC 31060 (Cabinets, wood, KD) |
| 400 | 0.5–0.75 lbs/cf | Deer antlers, gold leaf, bags of sawdust, large foam shapes | NMFC 152580 (Antlers, deer) |
| 500 | Under 0.5 lbs/cf | Ping pong balls, bags of feathers, inflatable kayaks (deflated), gold flakes | NMFC 168480 (Ping pong balls) — Highest rate |
Note: Density ranges are general guidelines. The actual class assigned by the NMFC may be influenced by stowability, handling, and liability factors that override density alone. Always verify the specific NMFC item number for your commodity.
NMFC Codes Explained — Real Examples
An NMFC code (also called an NMFC item number) is a specific numeric identifier assigned to a commodity description within the National Motor Freight Classification. The code ties a commodity to its assigned freight class, packaging requirements, and any special conditions that affect classification.
NMFC Code Structure
NMFC codes are typically 5–6 digit numbers, sometimes followed by a sub-item number. For example:
- NMFC 100240, Sub 1 — Office chairs, knocked down (KD), in boxes → Class 125
- NMFC 100240, Sub 2 — Office chairs, assembled, not crated → Class 150
- NMFC 100240, Sub 3 — Office chairs, assembled, crated → Class 125
Notice how the same product (office chairs) has three different classes depending on packaging. This is one of the most important and frequently misunderstood aspects of NMFC classification.
More Real NMFC Examples
| NMFC Code | Commodity | Class | Key Notes |
|---|---|---|---|
| NMFC 20220 | Automobile engines, crated | Class 70 | Must be crated; uncrated = Class 85 |
| NMFC 58750 | Computers, in original cartons | Class 92.5 | Original manufacturer packaging required |
| NMFC 46840 | Refrigerators, household | Class 85–125 | Class varies by density sub-item |
| NMFC 155540 | Tires, pneumatic, on rims | Class 77.5 | Unmounted tires = Class 110–125 |
| NMFC 36640 | Automobile parts, NOI (Not Otherwise Indicated) | Class 60–125 | Density-based; requires measurement |
| NMFC 87700 | Furniture, household, NOI | Class 125–250 | Wide range — packaging and density matter |
| NMFC 53120 | Clothing and wearing apparel, boxed | Class 70–125 | Density-tiered since 2024 NMFTA update |
| NMFC 113560 | Machinery, NOI, crated or boxed | Class 85–150 | Class based on density; crating required |
The “NOI” Catch-All Problem
Many shippers make the mistake of using generic “Not Otherwise Indicated” (NOI) NMFC codes when a more specific code exists for their product. NOI codes typically carry higher classes and broader density ranges, leaving more room for carrier interpretation — and reclassification. Always research the most specific NMFC code for your exact commodity before booking a shipment.
Freight Class in LTL vs. FTL Shipping
Freight class is primarily an LTL concept. In Less-Than-Truckload shipping, multiple shippers share trailer space, so carriers need a standardized way to price each shipment based on how much space and risk it consumes relative to others. The NMFC class system solves this problem.
In LTL freight, your freight class directly determines your rate per hundredweight (CWT). A Class 500 shipment might cost 10–15 times more per pound than a Class 50 shipment of the same weight, purely because of the space and handling differences.
In Full Truckload (FTL) shipping, freight class is technically irrelevant — you are purchasing the entire trailer, so the carrier is not concerned with how your freight interacts with other shipments. FTL rates are based on origin, destination, lane demand, and fuel costs, not NMFC class. However, carriers may still ask for commodity descriptions and NMFC codes for manifest purposes and cargo insurance calculations.
The decision between LTL and FTL also depends on shipment volume. As a general rule:
- LTL: shipments under approximately 10,000 lbs or fewer than 10–12 pallets
- FTL: shipments over 15,000 lbs or 15+ pallets, or when speed and direct transit are priorities
- Partial truckload: the middle ground, often more cost-effective for 6–12 pallets
For regional and local trucking moves, rates may be structured differently than national LTL, and some regional carriers use their own classification systems that blend NMFC classes with zone-based pricing.
2025 NMFTA Changes: The Shift to Density-Based Pricing
The most significant structural change to LTL classification in decades is now in full effect. Starting with NMFC Supplement 200 (2023) and accelerated through 2024–2025, the NMFTA has been systematically converting thousands of commodity items from fixed freight classes to density-based tiered classes.
What Changed
Previously, many commodities had a single fixed class regardless of their actual density. For example, household furniture might have been permanently assigned Class 125 regardless of whether a specific piece was dense or bulky. Under the new density-based system, the same NMFC code for furniture now carries multiple class tiers:
- Density ≥ 15 lbs/cf → Class 85
- Density 10–14.9 lbs/cf → Class 100
- Density 7–9.9 lbs/cf → Class 125
- Density 4–6.9 lbs/cf → Class 150
- Density < 4 lbs/cf → Class 175 or higher
Who Wins and Who Loses
The density-based transition creates clear winners and losers:
Winners (lower costs):
- Shippers of dense, heavy goods that previously had inflated fixed classes
- Industrial manufacturers shipping machinery, auto parts, and metal goods
- Food and beverage distributors shipping palletized bulk goods
Losers (higher costs):
- E-commerce shippers of bulky, lightweight consumer goods
- Furniture retailers shipping assembled or partially assembled pieces
- Apparel distributors shipping on-hanger garments
- Anyone shipping large, lightweight packaging (excessive void fill)
What This Means for Your Shipments
If you have not re-evaluated your freight classes since 2023, your rates may have changed significantly without any apparent reason. Carriers now routinely measure and weigh LTL shipments at the terminal using dimensioning machines (dim weight scanners), and if your declared class no longer matches the density-based tier, you will receive a reclassification charge on your invoice.
Key 2025 NMFTA Updates to Watch
- Clothing and wearing apparel (NMFC 53120): Fully density-tiered since NMFC Supplement 202 (2024)
- Household furniture (NMFC 87700): Density tiers now apply to most sub-items
- Electronics (multiple NMFC codes): Increased liability thresholds affecting high-value consumer goods
- Automobiles parts, NOI (NMFC 36640): Expanded density tiers replacing fixed classes for most sub-categories
Reclassification Fees and How to Avoid Them
A reclassification fee occurs when a carrier’s terminal inspector or automated dimensioning system determines that your shipment’s actual freight class is higher than what you declared on the Bill of Lading (BOL). The result is an invoice adjustment that includes:
- The difference in freight charges between your declared class and the reclassified class
- An administrative reclassification fee, typically ranging from $75 to $200 per shipment
- Potential re-inspection fees if the carrier conducted a physical inspection
Common Causes of Reclassification
- Wrong NMFC code: Using a generic NOI code when a specific code exists
- Inaccurate dimensions: Underestimating pallet height or overhang
- Packaging changes: Switching from crated to uncrated without updating the BOL
- Sub-item selection: Using the wrong sub-item for your packaging type
- Outdated classification: Using a class that was accurate in 2022 but has since been updated by the NMFTA
How to Dispute a Reclassification
If you believe a reclassification is incorrect, you can file a freight claim or rate dispute with the carrier. You will need to provide:
- The original BOL with your declared class and NMFC code
- Photographs of the shipment before pickup (with a ruler or tape measure visible)
- The specific NMFC sub-item and current NMFC tariff text supporting your declared class
- Weight scale receipts and dimension records
Disputes must typically be filed within 180 days of the delivery date under the Carmack Amendment, which governs cargo claims in interstate commerce.
How ExFreight Auto-Classifies Your Freight
One of the most common and costly mistakes in LTL shipping is incorrect freight classification. ExFreight’s platform eliminates this problem through automated classification built directly into the quoting workflow.
The ExFreight Classification Engine
When you enter a shipment into ExFreight’s system, the platform:
- Calculates density automatically from the dimensions and weight you enter — no manual formula required
- Searches the NMFC database based on commodity keywords and suggests the most accurate NMFC code and sub-item for your product
- Applies current density tiers from the latest NMFTA supplement — the system is updated whenever the NMFTA publishes new supplements, so you are always using current classifications
- Flags potential misclassification risk before you book — if the entered dimensions suggest a higher class than declared, the system warns you
- Returns real-time rates from 50+ LTL carriers based on the verified class, so the quote you see reflects what you will actually pay
Why Accurate Classification Saves Money Beyond the Rate
Accurate freight class does more than give you a correct upfront rate. It:
- Eliminates reclassification fees that average $125 per incident across the industry
- Prevents audit invoice adjustments that can arrive weeks after delivery
- Ensures cargo insurance coverage is calculated on the correct commodity value
- Speeds terminal processing, reducing the risk of missed delivery windows
- Builds carrier goodwill — repeated misclassification can result in carriers declining your freight
Whether your shipment is a domestic LTL move with our LTL freight service, a cross-country full truckload move, or an international import from China to the USA, accurate commodity classification is the foundation of cost-effective shipping.
Freight Class and International Shipping
It is important to understand that NMFC freight classes apply exclusively to domestic truck freight in the United States and Canada. International shipping — ocean freight, air freight, and international truck moves — uses entirely different rate structures.
International Equivalents
- Ocean freight (FCL/LCL): Rates are based on commodity type, origin/destination port pair, container size, and current market conditions. The Harmonized System (HS) code replaces the NMFC code for customs classification purposes.
- Air freight: Rates use dimensional weight (chargeable weight = actual weight vs. volume weight, whichever is greater, using a volumetric divisor of 139 or 166 depending on the carrier). See our guide comparing air freight vs. ocean freight for a full breakdown.
- Cross-border trucking: US-Mexico and US-Canada truck moves may use NMFC classes for the domestic portion but transition to customs-based commodity codes at the border.
FOB Terms and Freight Class Responsibility
When importing goods — for example, sourcing products from a manufacturer in China to the US or China to Canada — your Incoterms (particularly FOB terms) determine at what point you take responsibility for the shipment. Under FOB Origin, you are responsible for freight classification and costs from the factory floor. Under FOB Destination, the seller retains responsibility until the goods reach you.
For importers receiving LTL deliveries from US ports or warehouses, understanding freight class is essential — the domestic “last mile” LTL segment of an international shipment is fully subject to NMFC classification rules.
Frequently Asked Questions About Freight Class
1. What is the most common freight class?
Class 70 and Class 85 are the most frequently shipped classes in the US LTL market, representing dense industrial goods like auto parts, crated machinery, and packaged food products. Classes 125 and 150 are the most common for e-commerce and retail goods. Class 50 is technically the cheapest but rarely used for most commercial shipments, as achieving a density above 50 lbs/cf requires extremely heavy, compact cargo.
2. Can I change the freight class after a shipment has been picked up?
No. Once a shipment is picked up, the freight class declared on the Bill of Lading is the carrier’s reference for that shipment. If the carrier’s inspection reveals a discrepancy, they will issue a reclassification charge on the final invoice. You cannot voluntarily upgrade or downgrade the class mid-transit. If you discover an error before pickup, contact your freight broker or carrier immediately to issue a corrected BOL.
3. What happens if I don’t know my freight class?
Many LTL carriers and brokers will accept a shipment with “freight class to be determined” (TBD) and classify it at the terminal. However, this approach almost always results in the carrier assigning the highest plausible class for your commodity type — costing you significantly more than an accurate declaration. The better approach is to calculate density, look up the NMFC code, and declare an accurate class before booking. ExFreight’s platform does this automatically when you enter your shipment details.
4. Why do two different products with the same weight and dimensions get different freight classes?
Because density is only one of four classification factors. Two pallets can have identical dimensions and weights but very different freight classes if one commodity has high liability (electronics vs. rocks), poor stowability (irregularly shaped items), or requires special handling (fragile art glass vs. steel pipes). The NMFC assigns classes based on the full risk profile of the commodity, not just its physical density.
5. How often does the NMFTA change freight classes?
The NMFTA publishes multiple supplements per year. Major reclassification cycles typically occur once or twice annually, with targeted updates issued more frequently for specific commodity groups. Since 2023, the pace of changes has accelerated dramatically due to the density-based pricing transition. Shippers who have not audited their NMFC codes since 2022 should conduct a comprehensive review — especially for furniture, clothing, electronics, and automotive commodities, which have seen the most significant reclassifications.
Key Takeaways
- Freight class is determined by four factors: density, stowability, handling, and liability — with density now dominant under 2025 NMFTA rules
- There are exactly 18 freight classes ranging from Class 50 (densest, cheapest) to Class 500 (lightest, most expensive)
- Every commodity has a specific NMFC code — using the wrong code or sub-item is the leading cause of reclassification fees
- The 2025 NMFTA density-based pricing transition has reshaped rates for thousands of commodities — review your classes if you haven’t since 2022
- Freight class applies to domestic LTL/FTL trucking only — international shipments use HS codes, dimensional weight, or market-based pricing
- ExFreight’s platform automatically calculates density, matches NMFC codes, and returns verified rates from 50+ carriers — eliminating classification guesswork
Ready to ship? Get an instant LTL quote with automatic freight class calculation through ExFreight’s LTL freight service, or contact our team to discuss full truckload options for larger shipments.
