Understanding Freight Class and Shipping Rates
Quick answer: Freight class is a standardized rating system, run by the National Motor Freight Traffic Association (NMFTA), that groups freight into one of 18 classes from 50 to 500 based on density, handling, stowability, and liability. The lower the class number, the cheaper and easier freight generally is to ship — a pallet of steel bar stock (class 50) costs far less to move than a trailer of empty foam coolers (class 400) even if both weigh the same. Freight class matters most for less-than-truckload (LTL) shipments; if you're booking a full truckload, class has little to no bearing on your rate.
Key takeaways
- Freight class ranges from 50 (least expensive) to 500 (most expensive), based on a system maintained by the National Motor Freight Traffic Association (NMFTA) in its National Motor Freight Classification (NMFC) guide.
- Density is the single biggest factor in most class assignments — freight that's heavy for its size almost always rates lower than freight that's bulky but light.
- Misclassifying freight, even by accident, can trigger a reclassification and a rebill from the carrier after pickup, sometimes weeks later.
- Full truckload shipments generally don't use freight class for pricing — this system is built for LTL, where carriers combine multiple shippers' freight on one trailer.
What is freight class, exactly?
Freight class is a code that tells every carrier in the country the same thing about a shipment: how hard it is to move. The NMFTA created the National Motor Freight Classification system so shippers, brokers, and carriers could all speak the same language when quoting LTL freight, according to the NMFTA's published NMFC guide.
There are 18 classes, running from class 50 up to class 500 in set increments. Class 50 covers dense, easy-to-stack freight like bricks or bottled liquids. Class 500 covers freight that's light, awkward, or fragile — think empty gaylord boxes or ping pong balls. Everything else falls somewhere in between based on four factors the NMFTA weighs together.
Why does freight class exist in the first place?
It exists so carriers can price LTL freight fairly when they're stacking dozens of different shippers' pallets onto one trailer. On a full truckload, one customer's freight fills the whole trailer, so the carrier only cares about total weight, distance, and equipment type. On an LTL trailer, the carrier is trying to fit as much revenue-generating freight into a fixed amount of space and weight capacity as possible — and freight class is the tool that lets them price each pallet according to how much room and handling it actually consumes.
This is also why freight class rarely comes up if you're shipping full truckload. A 53' dry van truckload booking prices off weight, mileage, lane, equipment, and market conditions — not the NMFC code. If your freight fills a trailer on its own, you can generally skip the class conversation altogether.
What four factors determine a freight class?
The NMFTA sets class using four criteria, and density usually carries the most weight in practice:
- Density — how much space the freight takes up relative to its weight. Heavier-per-cubic-foot freight rates lower.
- Stowability — how easily the freight stacks or fits with other shipments. Odd shapes, hazardous materials, or freight requiring separation from other loads rate higher.
- Handling — whether the freight needs special care, like fragile glass or freight that can't be stacked. Extra handling requirements push the class up.
- Liability — how likely the freight is to get damaged, or damage other freight, and its value per pound. High-value or high-risk freight rates higher.
A worked example: a pallet of bottled water and a pallet of empty plastic coolers might take up the exact same footprint on a trailer. The water pallet could weigh 1,200 pounds and rate around class 60 because it's dense and stacks well. The coolers might weigh 150 pounds and rate around class 300 or higher because they're bulky, easily crushed, and waste trailer space relative to their weight. Same footprint, very different rate.
How much can freight class actually swing a shipping rate?
The swing can be dramatic — moving from class 50 to class 175 on the same shipment can more than double the LTL rate, even though nothing about the actual pallet changed except how it was classified. Carriers price lower classes cheaper because that freight is profitable to haul: it's dense, stacks well, and rarely gets damaged. Higher-class freight eats trailer space and handling time without adding proportional revenue, so carriers charge more to make it worth hauling.
| Class | Example freight | General rate impact |
|---|---|---|
| 50–85 | Steel, machinery parts, bottled goods | Lowest rates, dense and easy to handle |
| 92.5–125 | Auto parts, boxed electronics | Moderate rates |
| 150–200 | Furniture, some appliances | Higher rates, bulkier freight |
| 250–300 | Mattresses, lampshades, cabinetry | High rates, low density or fragile |
| 400–500 | Empty containers, ping pong balls | Highest rates, very low density |
Don't skip this: if a carrier's inspector opens a shipment and finds the actual density or packaging doesn't match what was declared on the bill of lading, they can reclassify the freight and rebill you after pickup — sometimes weeks after delivery. We cover how to avoid billing surprises like this in How to Read Your Freight Bill of Lading.
Why doesn't freight class apply to full truckload shipping?
Because a full truckload shipment isn't sharing trailer space with anyone else's freight, so the carrier has no reason to price it by density or stowability. What matters instead is total weight (up to roughly 45,000 pounds payload on a standard 53' dry van), the lane, fuel costs, and how quickly the carrier can turn the truck around for the next load.
This is one of the practical reasons shippers moving palletized or floor-loaded freight in volume switch from LTL to full truckload — not just for cost, but to remove classification disputes from the equation entirely. If you're weighing which approach fits your freight, we walk through the tradeoffs in Trucking Company vs. Freight Broker: Who Should You Hire? and in our comparison of General Freight vs. Specialized Hauling: Key Differences.
What should shippers check before quoting LTL freight?
Get the classification right before you book, not after the carrier inspects it at the dock. A few minutes of measuring now avoids a rebill later.
- Weigh the actual pallet, not an estimate from the packing slip.
- Measure length, width, and height to calculate cubic feet and density.
- Confirm whether the product has an existing NMFC code from a prior shipment or industry standard.
- Note any special handling needs — stackability, fragility, hazmat status.
- Ask the carrier to confirm the class before pickup if there's any doubt.
- Keep documentation of weight and dimensions in case of a dispute.
If your freight regularly runs close to a full trailer or ships on a recurring schedule, it may be time to stop fighting classification altogether and move to truckload. Full truckload and dedicated lanes price on weight and mileage, not NMFC codes, which is one reason shippers with steady volume find it easier to budget. Our team at PST Logistics runs 53' dry van and temperature-controlled truckload freight out of Naperville with the same truck and same driver from pickup to delivery — no cross-docking, no reclassification surprises, and dispatch that answers the phone around the clock. Call us to get a rate quote on your next dry van or reefer load.