Freight class is the classification system that determines how LTL (Less Than Truckload) carriers price your shipment. Every commodity shipped via LTL is assigned a class from 50 to 500 under the National Motor Freight Classification (NMFC) system, maintained by the National Motor Freight Traffic Association (NMFTA). The higher the class, the higher the per-pound shipping rate.
Getting your freight class wrong — either by guessing or using the wrong NMFC code — leads to reclassification fees, unexpected invoices, and billing disputes. This guide explains all 18 classes, how they are determined, and how to find the right class for your shipment.
How Freight Class Is Determined
Four factors determine a commodity's freight class:
1. Density
Density is the most important factor and is calculated as:
Density = Weight (lbs) / Volume (cubic feet)
Volume is calculated as: Length x Width x Height (in inches) / 1,728
Higher density commodities (heavy and compact) receive lower freight classes and lower rates. Lower density commodities (light and bulky) receive higher classes and higher rates. This makes sense — a pallet of steel takes up little space relative to its weight, while a pallet of pillows takes up a lot of space for very little weight.
2. Handling
How easy or difficult is the commodity to handle? Items that require special equipment, careful handling, or unusual loading procedures receive higher classifications. Examples: fragile goods, oversized items, or commodities requiring forklifts with special attachments.
3. Stowability
Can the commodity be loaded alongside other freight safely and efficiently? Items that are hazardous, oddly shaped, or cannot be stacked reduce trailer utilization and receive higher classes. Examples: live animals, flammable materials, or items with extreme dimensions.
4. Liability
What is the risk of damage, theft, or damage to other freight? Higher-value, more fragile, or more perishable commodities carry higher liability and receive higher classifications. Examples: electronics, pharmaceuticals, or perishable food items.
All 18 NMFC Freight Classes
| Class | Density Range (lbs/cu ft) | Type | Example Commodities |
|---|---|---|---|
| 50 | 50+ | Heavy/dense | Nuts and bolts, steel rods, sand |
| 55 | 35-50 | Dense | Bricks, hardwood flooring, cement |
| 60 | 30-35 | Moderately dense | Car parts, stone articles, bottled beverages |
| 65 | 22.5-30 | Moderately dense | Car accessories, bottled water, steel workbenches |
| 70 | 15-22.5 | Medium | Food items, automobile engines, unassembled furniture |
| 77.5 | 13.5-15 | Medium | Tires, bathroom fixtures, snowplows |
| 85 | 12-13.5 | Medium-light | Crated machinery, cast iron stoves, transmissions |
| 92.5 | 10.5-12 | Medium-light | Computers, monitors, refrigerators |
| 100 | 9-10.5 | Light | Boat covers, wine cases, canvas |
| 110 | 8-9 | Light | Cabinets, framed artwork, table saws |
| 125 | 7-8 | Light | Small household appliances, vending machines |
| 150 | 6-7 | Moderately light | Auto sheet metal parts, bookcases, assembled tables |
| 175 | 5-6 | Bulky-light | Clothing, couches, stuffed furniture |
| 200 | 4-5 | Bulky | Auto sheet metal parts (large), aluminum tables, packaged mattresses |
| 250 | 3-4 | Bulky | Bamboo furniture, mattresses, plasma TVs |
| 300 | 2-3 | Very bulky | Model boats, wood cabinets (knocked down), kayaks |
| 400 | 1-2 | Very light/bulky | Deer antlers, ping pong balls, empty crates |
| 500 | Less than 1 | Extremely bulky | Bags of gold dust, ping pong balls (loose), Styrofoam |
Note: Class 500 is extremely rare. Most LTL shipments fall between Class 50 and Class 200.
How Freight Class Affects LTL Cost
The relationship between freight class and shipping cost is direct and significant. A shipment classified as Class 150 will cost substantially more per hundredweight (per 100 lbs) than the same weight classified as Class 70.
Example comparison (same weight and distance, different class):
| Shipment | Weight | Class | Approximate Cost |
|---|---|---|---|
| Machine parts | 1,000 lbs | 70 | $450 |
| Assembled furniture | 1,000 lbs | 150 | $850 |
| Loose electronics | 1,000 lbs | 250 | $1,400 |
The cost difference is not linear — higher classes escalate rapidly. This is why getting the correct classification matters so much. An error of even one class level can mean hundreds of dollars in unexpected charges.
How to Look Up Your Freight Class
NMFC Code Database
The official source is the NMFC database maintained by NMFTA. Access requires a subscription ($99/year for basic access). You search by commodity description and receive the specific NMFC code and freight class.
Carrier Class Calculators
Many LTL carriers offer online freight class calculators on their websites. You enter the commodity description, weight, and dimensions, and the tool returns a suggested class. These are good starting points but are not authoritative — the NMFC code takes precedence.
Density-Based Classification
If you know your shipment's density, you can use the density ranges in the table above to estimate your class. Weigh the shipment and measure its dimensions (including packaging), calculate the density, and find the matching range.
Calculation example:
- Shipment weight: 800 lbs
- Dimensions: 48" x 40" x 48" (one pallet)
- Volume: (48 x 40 x 48) / 1,728 = 53.3 cubic feet
- Density: 800 / 53.3 = 15.0 lbs/cu ft
- Freight class: 77.5 (falls in the 13.5-15 range)
FAK (Freight All Kinds) Agreements
If you ship regularly via LTL, you may be able to negotiate a Freight All Kinds (FAK) agreement with your carrier. Under an FAK, all your shipments are rated at a single freight class regardless of the actual commodity — for example, all shipments treated as Class 70.
FAK agreements benefit shippers with a mix of commodity classes because they simplify pricing and often reduce the cost of higher-class shipments. Carriers offer FAK pricing to retain consistent volume — it is a volume discount in disguise.
To qualify for FAK pricing, you typically need:
- Consistent monthly LTL volume ($5,000+ in monthly freight spend)
- A relationship with a carrier or third-party logistics provider
- Willingness to commit to a minimum shipping volume
Common Classification Mistakes
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Guessing the class — Using an estimated class instead of looking up the correct NMFC code leads to reclassification fees. LTL carriers inspect shipments and will reclassify if the declared class is wrong.
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Not accounting for packaging — Freight class is based on the shipping density, which includes the pallet and packaging. A product that is Class 70 by itself may be Class 100 once palletized and shrink-wrapped if the packaging reduces density.
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Ignoring dimensional weight — If your shipment is lightweight but takes up significant space, carriers may use dimensional weight pricing, which can push the effective class higher.
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Not challenging reclassifications — If a carrier reclassifies your shipment, review the inspection report. If the reclassification is wrong, dispute it with the NMFC code documentation.
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Mixing commodity types on one pallet — Different commodities have different NMFC codes. Mixing can trigger reclassification of the entire shipment to the highest applicable class.
How to Reduce Your Freight Class
Reducing your freight class legally reduces your LTL shipping cost:
- Increase density — Pack more product into less space. Use smaller packaging, reduce void fill, and stack efficiently.
- Palletize properly — Stackable, well-secured pallets improve stowability (reducing class-impacting handling concerns).
- Negotiate FAK pricing — Consolidate your LTL volume with a single carrier and request a Freight All Kinds rate.
- Use accurate NMFC codes — Some commodities have multiple NMFC codes with different class assignments depending on packaging or preparation. Make sure you are using the code that correctly matches how your product is actually shipped.
Key Takeaways
Freight class is not arbitrary — it is a structured system based on density, handling, stowability, and liability. Using the correct NMFC code prevents reclassification fees and ensures your LTL quotes are accurate. If you ship LTL regularly, invest in an NMFC subscription, calculate your shipment density before quoting, and negotiate FAK pricing with your preferred carrier.
Every dollar saved on freight class optimization goes straight to your bottom line — and with LTL spend, the savings compound quickly across hundreds of shipments per year.