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Bills of lading

How AI Automates Freight Class, NMFC Lookups, and Density Calculations

Key Takeaways

  • AI automates LTL freight class by looking up the NMFC item from the product description and calculating the density-based class from weight and dimensions, then using that class on every quote and bill of lading.
  • Density now drives most freight class decisions. On July 19, 2025, the NMFC moved to a 13-subprovision density scale and reclassified more than 2,000 items.
  • Density is simple math that's easy to get wrong at volume: weight in pounds divided by cubic feet, for every handling unit on every shipment.
  • Wilson, by Cartage, is an AI agent that determines freight class for LTL shipments using the customer's SKU catalog, and explains how the class was calculated if a carrier reclassifies a shipment.
  • The customer stays responsible for the inputs: accurate SKU data, weights and dimensions are what make the class correct.

What is LTL freight class, and why does it cause so much rework?

A distributor books an LTL shipment at class 70. Two weeks later, the carrier's invoice arrives at class 100, with a reclassification fee. Nobody on the team can say how the original class was chosen. The product description was vague, the pallet dimensions were estimated, and the coordinator who booked it picked the class from memory.

LTL freight class is the classification carriers use to price less-than-truckload shipments, based on the National Motor Freight Classification (NMFC). A wrong class on the bill of lading leads to reclassifications, re-billing and disputes.

The NMFC is maintained by the National Motor Freight Traffic Association (NMFTA). In 2025, it changed significantly: according to Transport Topics, the update took effect on July 19, 2025, replaced the former density scale with a 13-subprovision density scale and reclassified more than 2,000 NMFC items. For many products, class now depends mainly on density, not on what the product is.

That makes the class only as accurate as the weight and dimensions behind it, on every shipment.

How is freight class determined under density-based NMFC rules?

Under density-based NMFC rules, freight class is determined by finding the product's NMFC item, calculating the shipment's density in pounds per cubic foot and matching that density to the item's class scale.

The 4 steps:

Identify the NMFC item from the product description.

Measure each handling unit: length, width and height in inches, including the pallet.

Calculate density: cubic feet = (length × width × height) ÷ 1,728; density = total weight in pounds ÷ cubic feet.

Match density to the class in the item's density scale.

Example: a pallet measuring 48 × 40 × 48 inches is 53.3 cubic feet. At 500 pounds, its density is about 9.4 pounds per cubic foot. That density, not the product name, decides the class on many items.

Doing this by hand for every pallet, on every shipment, is where errors creep in. For the broader LTL workflow, see how AI coordinates LTL shipments.

How does an AI agent determine freight class for every shipment?

An AI agent determines freight class by matching each order to the customer's SKU catalog, looking up the NMFC item, calculating density from weight and dimensions and applying the class to the quote and bill of lading. Traditional logistics software gives teams information. Wilson executes the work required to move shipments forward.

Step Trigger What Wilson does When a person steps in
1. Order intake An LTL order arrives from the ERP, spreadsheet, email or file drop Matches the order lines to the customer's SKU catalog If a SKU isn't in the catalog
2. NMFC lookup SKUs are matched Finds the NMFC item from the product description, or uses the NMFC code the customer already has If the description is ambiguous
3. Density calculation Weight and dimensions are known Calculates density and the density-based subclass for each handling unit If weight or dimensions are missing
4. Quote The class is set Requests quotes from approved carriers with the correct class, dimensions and weight Selections above a cost threshold, if configured
5. Documents The load is booked Puts the class and NMFC item on the bill of lading Not required
6. Reclassification A carrier changes the class Explains how the class was calculated and shares it with the team Deciding whether to dispute the change

The class flows into every downstream step, from quotes to documents. See carrier quoting automation and AI for freight documents.

What happens when a carrier reclassifies a shipment?

When a carrier reclassifies a shipment, the shipper needs to know how the original class was calculated, fast, to decide whether to accept or dispute the change.

Common reasons for reclassification:

  • Different dimensions: the carrier's dimensioner measured the pallet larger than declared.
  • Different weight: the actual weight didn't match the bill of lading.
  • Wrong NMFC item: the product description pointed to a different item.
  • Outdated class: the class came from before the 2025 density changes.

With Wilson, every class has a record of how it was calculated: the SKU, the NMFC item, the weight, the dimensions and the resulting density. When a reclassification comes in, Wilson explains the calculation so the team can respond with facts instead of guesses. Delays around freight are expensive in any form: ATRI found truck drivers were detained at 39.3% of stops in 2023.

How do teams keep control of freight class decisions?

Teams keep control of freight class by owning the inputs and setting the rules: accurate SKU data, clear escalation for missing information and a record of every calculation.

  • The customer owns the inputs: the SKU file, weights, dimensions and any NMFC codes it already uses. Accurate inputs are what make the class correct.
  • Escalation: missing dimensions, unknown SKUs and ambiguous descriptions go to the team instead of being guessed.
  • A record of every class: each calculation is stored on the shipment.
  • Approved carriers and configurable approvals: Wilson quotes and books only with approved carriers, within the company's approval rules. See Autonomy without rules is just another operational risk.

Timing depends on scope: most teams start on a few LTL lanes and expand from there. A useful metric on those first lanes is the reclassification rate: the share of shipments where the carrier changed the class, compared to the current baseline.

FAQs

  • Can AI determine LTL freight class? Yes. Wilson, by Cartage, determines freight class for LTL shipments by looking up the NMFC item from the product description and calculating the density-based class from weight and dimensions, using the customer's SKU catalog.
  • How is freight class calculated? Find the product's NMFC item, calculate density (weight in pounds ÷ cubic feet, where cubic feet = length × width × height in inches ÷ 1,728) and match the density to the item's class scale.
  • What changed in the NMFC in 2025? On July 19, 2025, the NMFC moved to a 13-subprovision density scale and reclassified more than 2,000 items, making density the main factor for many products.
  • Who is responsible for freight class accuracy? The shipper provides the inputs (SKU data, weights and dimensions) and is responsible for their accuracy. Wilson uses those inputs to determine the class and records how it was calculated.
  • What happens if a carrier reclassifies my shipment? Wilson explains how the original class was calculated (NMFC item, weight, dimensions and density) so the team can decide whether to accept or dispute the change.
  • Can AI use the NMFC codes we already have? Yes. If the customer already has NMFC codes for its products, Wilson uses them.
  • Does automating freight class require a TMS? Not with Wilson. Wilson replaces the TMS for freight execution and connects to the company's ERP, working from an ERP feed, scheduled file drop, spreadsheet, email or API.

Conclusion

Since the 2025 NMFC changes, LTL freight class depends more than ever on getting density right, on every pallet and every shipment. Doing that by hand creates reclassifications, re-billing and disputes nobody can explain. An AI agent turns freight class into a consistent calculation: SKU, NMFC item, weight, dimensions, density, class. Wilson, by Cartage, executes that work and keeps a record of every calculation, while the customer keeps ownership of the inputs. The practical first step is a few LTL lanes, measuring the reclassification rate against the current baseline; timing depends on scope, and most teams expand from there.

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