If you have ever requested an LTL quote and been asked for a “freight class,” you are not alone in wondering what it means. Freight class is one of the most misunderstood inputs in less-than-truckload shipping, yet it can change what you pay. This guide explains what freight class is, how NMFC codes fit in, and how to get it right the first time.
What is freight class?
Freight class is a standardized way of grouping commodities so carriers can price them consistently. The system comes from the National Motor Freight Classification (NMFC), which assigns commodities a class from 50 to 500. Lower numbers generally describe dense, durable, easy-to-handle freight; higher numbers describe light, bulky, fragile, or high-value freight that takes up more space or carries more risk per pound.
Because an LTL shipment shares a trailer with other customers’ freight, the carrier needs a common yardstick to decide how much your pallets cost to move. Freight class is that yardstick.
The four factors that determine class
The NMFC looks at four transportation characteristics:
- Density: how much space the shipment occupies relative to its weight. This is the biggest driver for most freight.
- Stowability: whether the freight can be stacked or loaded alongside other items, or whether it has odd dimensions or hazmat restrictions.
- Handling: how much special care, equipment, or labor the freight needs.
- Liability: the likelihood of damage, theft, or claims, and the value of the goods.
How to estimate density
Density is calculated in pounds per cubic foot. Measure the length, width, and height of your shipment in inches (include the pallet), multiply them together, divide by 1,728 to get cubic feet, then divide the total weight in pounds by the cubic feet.
For example, a pallet that measures 48 by 40 by 50 inches is about 55.6 cubic feet. If it weighs 500 pounds, its density is roughly 9 pounds per cubic foot. Carriers publish density tables that map that number to a likely class, which is why accurate dimensions matter so much.
What is an NMFC code?
An NMFC item number identifies a specific commodity, such as a type of machinery part or packaged consumer goods. Each item number is tied to a class (and some to several classes depending on density). The NMFC code on your bill of lading tells the carrier exactly what is being shipped, which supports the class used to price it.
You do not need to memorize codes. Your shipper, manufacturer, or a freight professional can usually identify the correct item number for your product.
Why the wrong class costs you money
If a class is understated at quote time, the carrier may inspect, reweigh, or reclassify the shipment and issue an adjustment after pickup. Those corrections often arrive as a surprise invoice. Overstating class does not help either, because you pay more than necessary.
The most common causes of mismatches are:
- Measuring the freight without the pallet or without overhang
- Estimating weight instead of using a scale
- Using the wrong commodity description
- Changing the packaging after the quote was given
Tips for getting the class right
Weigh and measure the shipment as it will actually travel, including pallet, wrap, and any crating. Keep a record of the dimensions and weight and use the same figures on your quote request and your bill of lading. If you ship the same product regularly, save the class and NMFC item number so every future quote starts from the same numbers.
If you are shipping in South Florida, our team can help you sanity-check the details before pickup. You can start with a quick quote or review our LTL freight services to see how pickups and deliveries are handled.
How technology helps
Modern carriers use dimensioners and scales at the dock to verify shipments. Tracking tools also give shippers visibility after pickup, so you know where freight is without calling. See how shipment tracking works with Go LTL.
Bottom line
Freight class combines density, stowability, handling, and liability into a single number that drives your LTL price. Measure carefully, use the right NMFC description, and keep your paperwork consistent. The result is fewer billing surprises and more predictable shipping costs.
Frequently asked questions
Can I ship LTL without knowing my freight class?
Usually you will need a class or enough information (dimensions, weight, and commodity) for the carrier to determine one. Providing accurate measurements is the best way to avoid reclassification later.
Does a higher freight class always mean a higher price?
Generally, yes, because higher classes describe freight that is lighter, bulkier, or riskier to move. Actual pricing also depends on distance, weight, and accessorial services.
Who sets the NMFC class?
The class system is maintained through the National Motor Freight Classification, which is published by a freight standards organization. Carriers apply it when pricing and inspecting shipments.