The Complete Guide to LTL Freight Classification

When you ship a pallet by LTL, your freight rides the same trailer as dozens of other shippers' freight, all bound for different destinations and consolidated through a hub-and-spoke network. For carriers to price thousands of different commodities consistently — and for a shipper in one state and a carrier in another to agree on exactly what is moving — the industry needs a common language: a standardized way to say "this is what I'm shipping and here's how hard it is to haul." That language is the National Motor Freight Classification (NMFC), published and maintained by the National Motor Freight Traffic Association (NMFTA), a non-profit membership organization of motor carriers.

Every commodity that moves by LTL is assigned an NMFC item number (identifying what it is, e.g. item 156600 for furniture) and a freight class from 50 to 500 (the rating category that prices it). Many items also carry sub-provisions that assign different classes depending on the commodity's density. The class is the dominant input to your LTL quote — bigger than weight or distance for many shipments. Get it right and you pay the correct rate; get it wrong and you face a reclassification charge after the carrier inspects the load.

The classification predates modern logistics software by decades, and that history matters: it was designed so that any carrier could rate any commodity the same way, which is why it leans on physical, inspectable characteristics rather than on what a product is "called." A "desk" isn't classed because it's a desk; it's classed because of how dense, stowable, and fragile the packaged desk is. For the full definition and the all-important NMFC-vs-freight-class distinction, see What is NMFC?

There are 18 freight classes, from class 50 (the densest, cheapest freight) to class 500 (the lightest, bulkiest, or highest-value freight). Lower class = denser = cheaper per pound; higher class = bulkier = more expensive. The full chart, with the density range and typical commodities for each class, is in Freight Class Explained, and every individual class has its own guide:

• Dense / low cost (50–77.5): 50, 55, 60, 65, 70, 77.5 — bricks, steel, flooring, auto engines, tires.
• Mid-range (85–125): 85, 92.5, 100, 110, 125 — machinery, appliances, cabinets.
• High / bulky (150–500): 150, 175, 200, 250, 300, 400, 500 — furniture, clothing, TVs, light bulky goods.

The classes are not evenly spaced in density — the bands narrow as you climb, so a small change in packed density matters far more at the high end than at the low end. A shipment sitting near a boundary (say between 100 and 110, or 150 and 175) can flip classes with an inch of extra height, which is why precise measurement pays off most for mid-to-high-class freight. Each class guide above explains that class's density range, the commodities that typically land there, how it compares to its neighbors, and the packaging moves that can shift it.

The NMFC classifies commodities on four transportation characteristics. For most general freight, density dominates — but the other three can fix or raise a class regardless of how dense the item is:

• Density — weight per cubic foot. Dense freight uses trailer space efficiently, so it costs less per pound. This is the primary driver for the majority of commodities, and it is the one characteristic you can directly influence through packaging.
• Stowability — how well the item loads alongside other freight. Oversized, excessively long, hazardous, or oddly shaped items stow poorly, waste surrounding space, and rate higher. Items that can't be stacked or that prevent other freight from stacking on them are penalized here.
• Handling — the care and effort to load and move it. Fragile, hazardous, or awkward items need special handling equipment or procedures, which raises the class.
• Liability — risk of damage, theft, or damage to adjacent freight, plus the commodity's value per pound. High-value goods (electronics, certain metals) can carry a class above what their density alone would suggest, because the carrier assumes more financial risk.

This is why two shipments of the "same" product can rate differently, and why density alone is an estimate, not the binding answer. A 200-lb pallet of dense machine parts and a 200-lb pallet of fragile glassware may have similar density but very different classes once handling and liability are weighed. When you use a density-based calculator, treat the result as a starting point and then confirm against the actual NMFC provision — especially for anything fragile, hazardous, or high-value.

If the system is "just density for most freight," why do so many shipments get reclassified? A few structural reasons:

• The same product has many classes. A catalog of "office chairs" can span several classes depending on whether they ship assembled, knocked-down, boxed singly, or palletized in bulk. There is no one class to memorize.
• Density isn't intuitive. People estimate by weight ("it's heavy, must be low class") when the class actually turns on weight relative to volume. A heavy but bulky item can rate high.
• The packaged unit ≠ the product. Pallets, crating, and overhang all count, and they're easy to leave out of a measurement.
• Provisions override density. Fragile, hazardous, high-value, or density-scale (Item 680) commodities don't follow the simple chart, and you can't tell which from the product name alone.
• It changes. The NMFC is revised over time; a class that was right last year can be reclassified, so a "known" class isn't permanently safe.

None of these are exotic edge cases — they're the everyday reasons a reasonable shipper guesses wrong. The defense is process: measure the real unit, calculate, and confirm the provision every time, ideally automatically.

Density is weight divided by volume, and it is the number that decides the class for the large majority of commodities. To find it:

The 1,728 is simply the number of cubic inches in a cubic foot (12³). Measure the fully packaged unit in inches, multiply the three dimensions to get cubic inches, divide by 1,728 for cubic feet, then divide the total weight by that.

Example: a 48 × 40 × 48 inch pallet weighing 500 lbs occupies (48×40×48)÷1,728 = 53.3 ft³, for a density of 9.4 lbs/ft³ — which lands in class 100. Keep the weight the same but let the load balloon to 48×40×60 inches and the volume jumps to 66.7 ft³, density falls to 7.5 lbs/ft³, and the class climbs to 125. Conversely, compress the same 500 lbs into 48×40×36 inches and density rises to 12.5 lbs/ft³ — class 85. The lesson: weight is fixed by the product, but volume is yours to manage, and volume is what moves the class.

The Freight Class Calculator runs this calculation automatically — enter weight and dimensions and it returns density plus the estimated class. The full density-to-class mapping, band by band, is in Freight Class Explained.

For most shipments, finding the class is a four-step process — three to estimate, one to confirm:

1. Measure the packaged unit. Length, width, and height in inches, including the pallet, crating, and any overhang. This is the most common place shippers go wrong: they measure the product, not the unit the carrier actually handles. Round up to the nearest inch.
2. Weigh the complete shipment as tendered. Total weight including packaging and pallet — the carrier re-weighs, so estimates that are off get corrected.
3. Calculate density and match the chart. Volume in cubic feet, then weight ÷ volume; your density falls into one of the 18 bands.
4. Confirm the NMFC provision. Density gives an estimate, but the binding answer is the commodity's actual NMFC item, which may fix a class regardless of density (for fragile, hazardous, or high-value goods) or rate it by a density scale (Item 680).

If your shipment lands near a class boundary, accuracy in steps 1–2 matters more than anywhere else — an inch of overhang or a few pounds can tip it into the next class. The full walkthrough, with worked examples for each step, is in How to Determine Freight Class. To skip the manual math, the Freight Class Calculator handles steps 3, and the NMFC Lookup handles step 4.

There is rarely a single "NMFC code" for a product category — most span several classes by sub-type and packaging. We have dedicated guides for the commodities shippers ask about most:

• NMFC code for furniture (class 70–400, depending on assembled vs. knocked-down)
• NMFC code for tires (typically class 77.5)
• NMFC code for auto parts (class 60–250)
• NMFC code for electronics (class 85–250)
• NMFC code for machinery (class 60–125)
• NMFC code for steel (class 50–70)

The pattern across all of these is the same: the product category isn't one class, it's a range, and where a given shipment lands depends on its packed density and any liability or handling provisions. "What's the NMFC code for X?" is really "what's the code for this X, packaged this way?" That's why each guide above shows the realistic class range and the sub-types that move within it, rather than pretending there's a single answer.

To look up any commodity by description and get its NMFC item number and class, use the NMFC Lookup, or resolve it programmatically with the NMFC API. If your product isn't in the list above, the lookup covers 3,000+ articles — search by a plain-English description and you'll find the matching item.

LTL carriers sell trailer space, so the class — which encodes how much space your freight uses per pound — is the biggest lever on price. A dense class-50 pallet and a bulky class-300 pallet can weigh the same yet differ several-fold in cost, because the bulky one occupies far more revenue-generating space. Carriers publish base rates per hundredweight (CWT) that climb steeply as class rises; the class you declare maps directly onto that rate table.

Worked example: imagine two 500-lb pallets shipping the same lane. Pallet A is knocked-down furniture in a tight 48×40×28 inch carton (31 ft³, ~16 lbs/ft³ → roughly class 70). Pallet B is the same furniture assembled, filling 48×40×70 inches (78 ft³, ~6.4 lbs/ft³ → roughly class 150). Same weight, same lane — but Pallet B can cost on the order of twice as much, purely because it consumes more than twice the trailer space per pound. Nothing about the product changed; only the packed density did.

Beyond class, an LTL quote also factors in actual weight, the origin-destination lane (ZIP-to-ZIP), fuel surcharges, and accessorials (liftgate, residential delivery, inside delivery, limited-access locations). But class is the lever you control most directly. For how the whole LTL pricing model and hub-and-spoke network fit together, see How LTL Shipping Works.

Because density drives class for most commodities, packaging is a genuine, repeatable cost lever — not a trick. Practical tactics that can move freight into a cheaper class:

• Right-size the carton. Every cubic inch of air you ship is space the carrier charges for but you don't fill. Cartons sized to the product raise density directly.
• Remove void fill where the product allows. Excessive dunnage inflates volume; use the minimum that protects the goods.
• Ship knocked-down (flat-packed). Disassembled furniture, shelving, and fixtures are dramatically denser than assembled, and the class difference is often two or more steps.
• Palletize tightly with no overhang. Overhang counts toward the cubic footprint and can also trigger stowability penalties.
• Consolidate light items. Combining several light cartons onto one well-packed pallet can raise the effective density of the handling unit.

Two cautions: the gain only counts if the carrier agrees on inspection, so re-measure the final packaged unit; and some commodities carry a fixed class regardless of density, where packaging won't help. Estimate the new density with the Freight Class Calculator before committing to a packaging change.

Carriers inspect freight. If they find the class understated, they reclassify the shipment and rebill the difference, often with an adjustment fee — one of the most common surprise charges in LTL. The avoidable mistakes:

• Measuring the product, not the packaged unit. Class is based on the shipment as tendered — pallet, crating, and overhang included.
• Defaulting to one "house" class for an entire catalog when products vary in density.
• Assuming density alone when the commodity's provision fixes a class for stowability, handling, or liability reasons.

The reliable workflow is measure → calculate → confirm the provision, documented on the bill of lading. A correct, documented NMFC item number is also your strongest defense if a charge is ever disputed: it shows you classified in good faith against the actual provision rather than guessing.

Reclassification charges are not just the rate difference — carriers commonly add an inspection or correction fee on top, and the corrected (higher) class can also pull in accessorials or minimums you didn't quote. A single mis-class on a recurring lane multiplies across every shipment until someone catches it, which is why systematic, documented classification beats per-shipment guesswork. Automating the confirm step with the NMFC API keeps every shipment rated correctly without manual lookups, and surfaces the exact NMFC item to print on the BOL.

Some commodities are classified under density-based provisions rather than a single fixed class — the NMFC's Item 680 family is the best-known example. Instead of "this product is class X," the provision says "rate this product by its density," using a graduated scale and a set of notes (Note 2A, 2B, 2C) that handle different dimension and packaging scenarios. The result is that the same product can legitimately move at several classes depending on how it's loaded.

Density provisions are common for commodities that vary widely in how they ship — the same SKU palletized one way versus another. If your commodity falls under a density-based item, you genuinely must calculate density per shipment; there is no shortcut class. The NMFC API exposes the Item 680 Note 2A/2B/2C calculators directly so you can resolve these automatically, and the Freight Class Calculator covers the straightforward density case.

A quick glossary of terms you'll meet when classifying and shipping LTL freight:

• NMFC — National Motor Freight Classification, the standard that assigns commodities an item number and freight class.
• Freight class — the 50–500 rating category that drives the LTL rate. See Freight Class Explained.
• Density — weight per cubic foot (lbs/ft³); the main driver of class for general freight.
• LTL — less-than-truckload; freight too large for parcel but not filling a trailer, sharing space with other shippers.
• BOL — bill of lading; the shipping contract and document where you declare the NMFC item and class.
• CWT — hundredweight (per 100 lbs); the unit LTL base rates are quoted in.
• Accessorial — an add-on service charge (liftgate, residential, inside delivery, limited access).
• Reclassification — a carrier correcting the class after inspection and rebilling the difference.

Looking up classes by hand works for a few shipments a week; it does not scale to a TMS, a quoting tool, a 3PL, or a high-volume shipper. Manual lookups are slow, inconsistent between staff, and a common source of reclassification charges when someone guesses. The NMFC API provides programmatic NMFC search across 3,000+ articles with sub-item density breakdowns, plus density and Item 680 (Note 2A/2B/2C) calculators — so your application resolves the authoritative class on every shipment automatically, with the NMFC item number ready to print on the bill of lading.

The same API also covers multi-carrier terminal locations across ten LTL/freight carriers and 4,400+ global seaports, so a shipping application can classify freight and route it through real carrier networks from one integration. Start with the free NMFC Lookup to see the data, read the API documentation to integrate it, or grab the Postman collection to try every endpoint.

If you remember nothing else about freight classification:

• Freight class (50–500) is the biggest driver of your LTL rate — bigger than weight or distance for most shipments.
• For general freight, density sets the class; lower density means a higher, more expensive class.
• Always measure and weigh the fully packaged unit, not the product.
• Density is an estimate — the binding answer is the commodity's actual NMFC provision, which can fix or scale the class for stowability, handling, liability, or (Item 680) density reasons.
• Better packaging is a real, repeatable way to lower your class and your cost.
• Confirming and documenting the NMFC item on the bill of lading is what prevents reclassification charges.

From here, dig into any spoke: What is NMFC?, Freight Class Explained, How to Determine Freight Class, or How LTL Shipping Works — or just try the Freight Class Calculator.