Two shippers send nearly identical pallets down the same lane in the same week. One pays $340, the other $610. Nothing about the truck, the miles, or the fuel changed. The difference was a three-digit number on the bill of lading: the freight class.
Freight class is the most misunderstood line on an LTL quote, and the one that quietly costs shippers the most money. Get it right and rates stay predictable. Get it wrong and a reclassification notice lands weeks after delivery with an invoice nobody budgeted for. As of July 2025, the rules governing how that number gets assigned changed more than they have in a generation.
What Freight Class Actually Is
Freight class is a standardized rating telling an LTL carrier how difficult and expensive your shipment is to move. It is maintained by the National Motor Freight Traffic Association (NMFTA) and published in the National Motor Freight Classification, usually shortened to NMFC.
There are 18 freight classes, from class 50 at the low end to class 500 at the high end, and the scale runs inversely to what most people expect. A low class means dense, sturdy, easy-to-load freight and a lower rate per hundredweight. A high class means light, bulky, fragile, or high-value freight and a higher rate.
The logic makes sense once you stop thinking about weight: an LTL carrier sells trailer space, not pounds. A pallet of bricks and a pallet of ping pong balls occupy the same floor position, but only the bricks let the carrier bill thousands of pounds against it. Freight classification exists so the carrier gets paid for space, not just the scale ticket.
The July 2025 NMFC Overhaul: Density Became the Default
For most of the system's history, freight class was tied to what you were shipping. The NMFC listed thousands of commodities, each with an item number and a fixed class attached. Whether your pallet was densely packed or mostly air did not enter into it.
On July 19, 2025, the NMFTA changed that. Roughly 2,000 commodity listings were converted from fixed classes to density-based classification. The question is no longer only what is in the box. It is how much that box weighs per cubic foot. This is the largest structural change to freight classification in decades, and a class you have used for years may no longer be correct.
The 13-Subprovision NMFC Density Scale
Density-based commodities are rated against a scale of density brackets, each called a subprovision, or sub. Before July 2025 that scale had 11 subs and bottomed out at class 60. It now has 13 and reaches down to class 50. Here is the current freight class chart, in pounds per cubic foot (pcf):
Sub 1: less than 1 pcf equals class 400
Sub 2: 1 up to 2 pcf equals class 300
Sub 3: 2 up to 4 pcf equals class 250
Sub 4: 4 up to 6 pcf equals class 175
Sub 5: 6 up to 8 pcf equals class 125
Sub 6: 8 up to 10 pcf equals class 100
Sub 7: 10 up to 12 pcf equals class 92.5
Sub 8: 12 up to 15 pcf equals class 85
Sub 9: 15 up to 22.5 pcf equals class 70
Sub 10: 22.5 up to 30 pcf equals class 65
Sub 11: 30 up to 35 pcf equals class 60
Sub 12: 35 up to 50 pcf equals class 55
Sub 13: 50 pcf or greater equals class 50
Notice how uneven the brackets are at the light end. Between 1 and 2 pcf you sit in class 300, but slip below 1 pcf and you jump to class 400. On light freight, one inch of packaging height can move you a full class.
Classes 50 and 55 Joined the Density Scale
The old scale stopped at class 60 for anything 30 pcf or denser, so a pallet at 32 pcf and one at 55 pcf rated identically. Subs 12 and 13 fix that: freight at 35 pcf or above now qualifies for class 55, and freight at 50 pcf or above qualifies for class 50.
If you ship heavy, compact product such as fasteners, canned goods, tile, machined metal parts, or bottled liquids, this is worth real money. Shippers who never rechecked after July 2025 are very likely still paying class 60 rates on freight that now qualifies for class 50. Nobody sends a refund for that. You have to catch it yourself.
Handling, Stowability, and Liability Are Now Flagged Separately
Density did not swallow the whole system. The NMFTA kept the other three factors but pulled them into their own identifiers rather than baking them invisibly into a commodity class. If your freight needs special handling, stows poorly, or carries elevated liability risk, that is flagged separately, so a shipment can calculate to class 70 on density and still rate higher. The density scale is the starting point, not always the finish line.
What Comes Next in 2026
Docket 2026-1 landed on February 6, 2026, converting more listings to density-based rating, and further dockets are expected. Freight classification is no longer a set-and-forget field in your TMS.
The Four Factors Behind Every Classification
Every class assignment traces back to four characteristics defined by the NMFTA.
Density is weight divided by volume. It is the dominant factor after the 2025 changes and the only one of the four you can directly engineer.
Stowability is how well the shipment loads alongside other freight. Long pipe, odd shapes, protruding parts, anything unstackable, and hazardous materials that cannot ride beside certain commodities all stow badly and rate higher.
Handling is whether the freight moves through a normal dock on a normal forklift. Items needing special equipment, temperature control, or careful manual handling raise the class.
Liability is the exposure the carrier absorbs if something goes wrong: value per pound, theft appeal, perishability, fragility, and whether the freight can damage cargo around it. Electronics and pharmaceuticals rate high however tightly they are packed.
How to Determine Your Freight Class Step by Step
Step 1: Measure the shipment as it ships, not the product alone. Include the pallet, shrink wrap, crating, and any overhang, and take the longest, widest, and tallest points. This is the most common source of misclassification: a carton measuring 48 by 40 by 48 inches on a six inch pallet is a 54 inch shipment, not a 48 inch one. Round up to the next full inch, because the carrier will.
Step 2: Convert to cubic feet. Multiply length by width by height in inches, then divide by 1,728, the number of cubic inches in a cubic foot.
Step 3: Calculate density. Divide total shipment weight in pounds, pallet and packaging included, by those cubic feet. Use a scale weight, not a bill of materials estimate. The result is your density in pounds per cubic foot.
Step 4: Match the density to the scale above and take the class for that bracket, then confirm the commodity's NMFC listing. If it is density-based, the sub governs. If it carries a fixed class or a handling or liability provision, the published item governs instead.
A Worked Freight Class Calculation
You are shipping steel brackets on a 48 by 40 inch pallet. Wrapped tightly, the load stands 45 inches on a 6 inch pallet, so shipping height is 51 inches. Scale weight with the pallet is 1,500 pounds.
Volume: 48 times 40 times 51 equals 97,920 cubic inches, or 56.7 cubic feet. Density: 1,500 divided by 56.7 equals 26.5 pcf. That lands in Sub 10, so the freight class is 65.
Now change one thing. The same freight is wrapped loosely on a different shift and stands 62 inches. Volume becomes 68.9 cubic feet, density drops to 21.8 pcf, and you land in Sub 9 at class 70. Same product, same weight, same lane, a full class higher because of eleven inches of air.
NMFC Codes Versus Freight Class: Not the Same Thing
These two terms get used interchangeably and they should not be. The NMFC code, or item number, identifies the commodity. It is typically a five or six digit number, often with a sub attached, written like 156600-3. It answers what the freight is. The freight class is the rating that comes out of that listing, the three-digit number the carrier's pricing engine multiplies against. It answers what the freight costs to move.
One NMFC code can produce several classes depending on which density sub you land in, and the 2025 changes made that far more common. That is why a rate confirmation should show both. If your bill of lading lists a class with no NMFC item number behind it, you are asking the carrier to guess, and carriers do not guess in your favor.
What Reclassification Actually Costs You
Carriers verify now. Most major LTL carriers run automated dimensioning equipment that photographs, measures, and weighs freight moving through the terminal, so an inaccurate class passing unnoticed is no longer realistic.
When the measurement does not match the bill of lading, the carrier reissues the invoice at the corrected class and adds an inspection fee. That bill arrives weeks after delivery, once the shipment is closed and your customer invoiced, so the margin you thought you had is gone. There is a second cost: pricing teams look at correction rates when building annual agreements, so a shipper who generates constant reclassifications gets priced defensively the following year.
Four Freight Classification Mistakes That Cost the Most
1. Reusing last year's class. The July 2025 overhaul moved roughly 2,000 listings. Assume some of yours moved.
2. Ignoring subs 12 and 13. Dense freight still rated at class 60 out of habit is overpaying, sometimes by two full classes.
3. Leaving the NMFC item number off the bill of lading, which invites the carrier's interpretation instead of yours.
4. Using estimated weights. Bill of materials weight and scale weight diverge once packaging is added.
How to Use Density to Lower Your LTL Costs
Density is the one classification factor you control, which makes packaging one of the highest-return levers in LTL cost management, and one most shippers never pull.
Reduce the height, because air at the top of a pallet is the most expensive air you will ever ship. Eliminate overhang, which adds billable length and width without adding a pound. Consolidate, since two half-full pallets to the same consignee are almost always worse than one full one. And rethink cartons sized for retail shelf appeal rather than freight: 30 percent void space gets billed at the freight rate for the life of that SKU.
Then recheck after any packaging change. A new carton supplier, pallet, or stacking pattern can move you across a density break unnoticed until reclassification notices arrive.
When Freight Class Stops Mattering
Freight class is an LTL concept. It exists because multiple shippers share a trailer and the carrier needs a defensible way to divide the cost of that space. Once a shipment gets large enough, class becomes irrelevant: most carriers shift to volume LTL or partial truckload pricing around 6 to 12 pallets or 8 to 14 linear feet, and full truckload pricing ignores classification entirely.
This is why the density conversation and the mode conversation belong together. A shipper rating bulky, low-density freight at class 175 or higher across 8 pallet shipments often pays more in LTL than a partial or dedicated truck would cost. If your freight is light and bulky, classification will never be your friend, and the fix is a different mode rather than a better class.
Where a Freight Broker Fits In
A broker sees which commodities are drawing inspections and which listings moved in the latest docket. We can also model the same shipment across LTL, volume LTL, and truckload before it moves, so the class question and the mode question get answered together, which is where most of the savings live.
And we handle disputes. Carriers make classification errors, and a documented challenge backed by photographs, scale tickets, and the correct NMFC item number gets corrections reversed more often than shippers expect. Most shippers just pay, because chasing one correction is not worth an afternoon. Across a year of volume, it is worth it.
The Bottom Line
Freight class is not paperwork. It is pricing. Under the density-based NMFC rules that took effect in July 2025, the number on your bill of lading is a direct function of how tightly you pack a pallet, and it moves whenever your packaging moves.
Three actions are worth taking this quarter. Recalculate density on your top ten LTL commodities against the current 13 subprovision scale. Check whether any dense freight still rated at class 60 now qualifies for class 55 or 50. And confirm every bill of lading carries both the NMFC item number and the class, so carriers price your freight instead of interpreting it.
If you would rather run that audit with someone, our team at The American Truck can review your recent LTL invoices and classification history and show you where the savings are hiding. Get in touch and we will look at your lanes.