Freight Class

What freight class actually is

Freight class is a pricing category managed by the National Motor Freight Traffic Association (NMFTA), the same organization that maintains the NMFC commodity code database. The system has been around since 1936 and is still the foundation of every LTL carrier tariff in the US.

The concept is simple: freight that's dense, stackable, and easy to handle is cheap to move. Freight that's light, bulky, fragile, or hazardous takes up truck space without contributing much weight. Carriers lose money on low-density freight unless they charge more for it. The class system formalizes that into 18 tiers.

Every time you ship LTL with a traditional carrier, the freight class on your bill of lading determines your base rate. That rate gets modified by fuel surcharges, accessorial fees, and your contract discount, but the class is the starting point. A shipment that should be Class 70 but gets classified as Class 100 can cost 30-50% more on the same lane with the same carrier.

The four factors that determine freight class

The NMFTA evaluates four characteristics when assigning a class to a commodity. In practice, density dominates the other three for most general freight.

Density is weight per cubic foot. It accounts for about 80% of classification decisions. A 48x40x48 pallet weighing 800 lbs has a density of 15 PCF, putting it in Class 70. The same pallet at 400 lbs drops to 7.5 PCF and Class 125. Same physical space, very different cost.

Stowability is how well the freight fits alongside other shipments in a trailer. Odd shapes, protruding pieces, or loads that can't be stacked or double-decked reduce stowability. A standard palletized shipment with flat surfaces scores well. A crated engine block with lifting lugs protruding 6 inches scores poorly.

Handling difficulty covers whether special equipment is needed. Freight requiring forklifts with specific attachments, top-loading restrictions, or temperature control adds handling cost. Standard pallets on a standard dock are baseline. Anything requiring extra care or equipment pushes the class up.

Liability is the risk of damage, theft, or spoilage during transit. Perishable goods, high-value electronics, and hazardous materials carry higher liability. A pallet of canned soup has low liability. A pallet of smartphones has high liability. This factor can override density for certain NMFC codes, assigning a higher class than the density alone would dictate.

All 18 freight classes: complete chart with examples

This table shows every freight class, its density range in pounds per cubic foot (PCF), and real commodity examples. Bookmark this for reference when filling out bills of lading.

Calculate your freight class

Enter your shipment dimensions and weight below. The calculator returns your density in PCF and maps it to the corresponding freight class from the table above.

Need the full tool with promo code and quote flow? Use the standalone freight class calculator.

How freight class affects your shipping cost

Freight class is a multiplier on your base rate. Moving from Class 70 to Class 100 on the same lane with the same carrier can increase the rate by 30-50%. Moving from Class 100 to Class 200 can double it or more. The relationship is not linear: each jump up in class costs proportionally more than the last.

Here's why this matters in practice. Two shippers sending identical-looking pallets from Atlanta to Chicago will pay different amounts if one pallet is 18 PCF (Class 70) and the other is 9 PCF (Class 100). The lighter pallet takes the same trailer space but the carrier earns less weight-based revenue from it. The class system compensates by charging more per pound for lower-density freight.

This is also why reclassification hurts so much. If you quote Class 70 and the carrier reclassifies to Class 100 at the terminal, you don't just pay a small penalty. You pay the Class 100 rate on the entire shipment, retroactively. On a 6-pallet shipment moving 700 miles, that difference can be $200-$400 per load.

How to avoid reclassification charges

Reclassification is the single most common cause of LTL invoice disputes. Carriers inspect freight at their origin terminal. If the actual density or commodity doesn't match what's on the BOL, they assign a new class and bill accordingly. The revised invoice shows up 2-4 weeks after delivery.

Measure on a calibrated scale. Estimated weight is the most common source of error. A 50-pound difference on a single pallet can shift the density enough to change the class. Weigh every shipment.

Measure extreme outer dimensions. If your freight overhangs the pallet by 2 inches on each side, the carrier will measure a 52x44 footprint, not 48x40. That increases your cubic footage and reduces density. Shrink wrap bulge counts too.

Look up the NMFC code, not just the density. Some commodities have fixed classes that override density. Shipping electronics classified by density at Class 85 could get reclassified to Class 125 if the carrier identifies them under a fixed-class NMFC code for electronic equipment.

Build a classification reference by SKU. If your warehouse ships the same 20 products repeatedly, create a lookup table with the correct NMFC code and freight class for each. Tape it to the shipping desk. This prevents floor staff from guessing.

NMFC codes and freight class: how they connect

Every commodity shipped via LTL has an NMFC code assigned by the NMFTA. The code identifies what the commodity IS. The freight class is the pricing tier that code maps to. Think of it as: the NMFC code is the product, the freight class is the price tag.

Many NMFC codes have sub-codes where the freight class varies by density. NMFC 116030 (wooden furniture) has 5 sub-codes: dense solid-wood pieces classify at Class 70, while lightweight assembled shelving might classify at Class 200. Same NMFC item number, different class based on actual shipment density.

Other NMFC codes have fixed classes regardless of density. Hazardous materials, fragile goods, and high-liability items often fall into this category. The NMFC code assigns a specific class that cannot be changed by measuring the shipment differently.

Use the NMFC code lookup tool to find the correct code for your commodity before filling out your bill of lading.

How Warp eliminates freight class from the equation

Warp prices by pallet, not by freight class. You enter your pallet count, weight, and dimensions. You get an all-inclusive rate back. No NMFC code lookup, no density calculation, no class assignment needed at booking.

Because the pricing doesn't use freight class, there's no mechanism for reclassification after delivery. The rate at booking is the rate on the invoice. For shippers who have dealt with reclassification disputes, back-billing surprises, or AP complexity from class-based adjustments, this is the structural difference.

The freight class system was built for a paper-based freight era. It works, but it creates a pricing model where the final cost isn't known until after the carrier inspects the freight. Per-pallet pricing solves that by making the cost deterministic at the moment you book.

Freight class FAQ