Rating & classification

LTL freight class and NMFC codes, explained

LTL pricing runs on freight class, and freight class runs on the NMFC. Here is what the numbers on your BOL actually mean, how to calculate density, and where the authoritative answers live.

Create an LTL BOL — free Calculate density

The short answer

The National Motor Freight Classification (NMFC) is the catalog LTL carriers rate from. Every commodity gets an item number, and each item maps to a freight class from 50 to 500. Lower classes are denser, easier, lower-risk freight — and cheaper to ship. Class 50 is the territory of steel fittings; class 500 is the territory of ping-pong-ball freight: light, bulky, or fragile.

The class on your BOL is what the carrier bills against — and what their inspection team checks first when the numbers look wrong. That makes the NMFC item and class fields two of the most consequential lines on the document.

The four factors behind every class

The NMFC classes commodities on four transportation characteristics. Density does most of the talking, but all four are in play:

Density

Weight per cubic foot. The heavy hitter of classification — dense freight costs less to move because it uses trailer space efficiently.

Stowability

How well the freight travels with other freight. Odd shapes, extreme length, hazmat rules, and “do not stack” loads all stow worse than a square pallet.

Handling

How much care the freight demands. Fragile, top-heavy, or special-equipment loads cost more to move safely than a shrink-wrapped pallet.

Liability

Value per pound and the risk of damage or theft. High-value or easily damaged commodities carry more risk for the carrier, and class reflects it.

Density: the part you can calculate

Density is the one classification input you can compute yourself, and it is simple arithmetic:

density (lb/ft³) = weight (lb) ÷ volume (ft³)
volume (ft³) = (L × W × H in inches) ÷ 1,728

Worked example — one pallet, 48 × 40 × 60 inches, weighing 1,150 lb:

volume = 48 × 40 × 60 = 115,200 in³

volume = 115,200 ÷ 1,728 ≈ 66.7 ft³

density = 1,150 ÷ 66.7 ≈ 17.2 lb/ft³

In DockBOL you never touch the formula: enter length, width, height, and gross weight on a commodity line and the density calculates live, right next to the class field.

The density guidelines carriers reference

For density-based commodities, carriers reference a scale like this one when they inspect freight. It is shown here for orientation — read the caveat below before you write a class on anything.

Commonly referenced density-based freight class guidelines
Density (lb/ft³)	Guideline class
50 lb/ft³ or more	50
35 – 50	55
30 – 35	60
22.5 – 30	65
15 – 22.5	70
13.5 – 15	77.5
12 – 13.5	85
10.5 – 12	92.5
9 – 10.5	100
8 – 9	110
7 – 8	125
6 – 7	150
5 – 6	175
4 – 5	200
3 – 4	250
2 – 3	300
1 – 2	400
Less than 1	500

Orientation, not classification

This table is the commonly referenced density scale, provided for orientation only. The NMFC is a copyrighted publication that is updated through the year, and item-specific provisions, packaging rules, and exceptions override density. Confirm every class against the current NMFC (NMFTA ClassIT+) or with your carrier before tendering freight.

What a wrong class costs

Carriers run inspection programs at their terminals: freight gets reweighed, remeasured, and the description on the BOL gets checked against the NMFC. When the paperwork and the freight disagree, the carrier reclasses or reweighs the shipment — and an adjusted invoice arrives weeks later, often with an inspection fee attached.

Repeat offenders get audited more. The defense is boring and effective: an accurate commodity description, real dimensions and scale weights, and a class you actually confirmed — on every BOL, every time.

What DockBOL does — and doesn't do

Does: calculates density live from your dimensions and weight; gives every commodity line NMFC item, sub, and class fields; saves your confirmed values as reusable presets; totals weights and pieces across the document.

Doesn't: look up or assign NMFC items or classes, and it never will from a typed description. Your saved presets are your own convenience data — not official classification. The class on the document is yours to confirm, and DockBOL keeps that responsibility visibly with you.

Try the density calculator on a commodity line

Freight class & NMFC — FAQ

Who assigns NMFC item numbers and freight classes?

The National Motor Freight Traffic Association (NMFTA) publishes and maintains the NMFC. Carriers, shippers, and other stakeholders participate in the classification process, but the published NMFC is the reference carriers rate from. Your job as a shipper is to find the item that matches your commodity and put its number and class on the BOL — NMFTA's ClassIT+ is the official lookup tool, and your carrier or 3PL can help.

Is the NMFC free to look up?

No. The NMFC is a copyrighted publication, licensed through NMFTA's ClassIT+ service. That is exactly why DockBOL does not bundle a classification database or pretend to look classes up — and why you should be wary of any free tool that claims to assign an authoritative class from a typed description.

Does density alone determine my freight class?

Only for density-based commodities — items the NMFC classes on a density scale. Many commodities have a fixed class regardless of density, and plenty of items carry special provisions, packaging requirements, or exceptions. Density is the starting point, not the ruling. Confirm against the current NMFC or with your carrier.

What happens if the class on my BOL is wrong?

Carriers inspect freight at their terminals — weighing, measuring, and checking descriptions against the NMFC. A mismatch becomes a reclass or reweigh: an adjusted invoice, often with an inspection fee, arriving weeks after delivery. Repeated mismatches put a shipper on the audit list. Accurate descriptions, dimensions, and weights on the BOL are the defense.

What's the difference between an NMFC item number and a freight class?

The item number identifies the commodity in the NMFC catalog — for example, a specific entry for a type of machinery, with any packaging notes and sub-items. The freight class (50–500) is the rating category that item maps to; for density-based items, the same item number can map to different classes at different densities. The BOL carries both: the item number says what it is, the class says how it rates.

Do I need NMFC details on every BOL?

For LTL, yes — the class and item number are what the carrier rates the shipment against, and leaving them off invites a worst-case default or an inspection. For full truckload, freight is usually priced by the load, not by class, so NMFC detail matters less. When in doubt, put accurate classification data on the document.

Keep reading

What is a bill of lading?

The document the class lives on — and why carriers bill from what it says.

Bill of lading barcodes

Code 128 and GS1-128 — how the identifiers on your BOL get scanned, not keyed.

Straight bill of lading generator

Build the LTL document with NMFC fields and live density math — free.

Bill of lading template PDF

Fill the template online and download a print-ready US Letter PDF.

Sources & scope

Updated August 22, 2026. Scope: U.S. LTL classification education. DockBOL calculates density only; current NMFC data and carrier requirements determine an applicable class.

NMFTA — freight classification overview — classes 50–500 and four transportation characteristics
NMFTA classification glossary — current definitions for NMFC, class, and density

You bring the class — DockBOL does the math

Density calculated live, NMFC fields on every line, and your confirmed classes saved as presets for the next load. Free, no account, no classification guesswork.

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