Freight Class Calculator (LTL Shipping)

Freight class is the primary driver of your base LTL rate. Carriers price per 100 lbs (per hundredweight, or CWT), and the rate per CWT rises sharply as the class number increases — a Class 500 shipment can cost 5–10× more per pound than a Class 50 shipment. If you declare the wrong class on your bill of lading and the carrier's freight inspector re-weighs or re-cubes your shipment at the destination dock, they will issue an 'inspection reclassification' and invoice you for the difference plus a fee. Knowing your correct class before you book prevents billing disputes and allows you to compare carrier quotes on a consistent basis.

The standard NMFC density method uses two formulas. First, calculate the volume in cubic feet: Volume (ft³) = (Length × Width × Height) ÷ 1,728, where dimensions are in inches. Second, calculate density: Density (lbs/ft³) = Total Weight ÷ Volume. You then look up the density in the NMFC freight class table: Class 50 applies to shipments with density ≥ 50 lbs/ft³, and the class number rises as density falls, all the way to Class 500 for shipments below 1 lb/ft³. Some commodity types have a fixed NMFC class regardless of density — always verify with your carrier or the NMFC directory for regulated commodities.

The 18 NMFC freight classes and their density thresholds are: Class 50 (≥ 50 lbs/ft³), Class 55 (35–50), Class 60 (30–35), Class 65 (22.5–30), Class 70 (15–22.5), Class 77.5 (13.5–15), Class 85 (12–13.5), Class 92.5 (10.5–12), Class 100 (9–10.5), Class 110 (8–9), Class 125 (7–8), Class 150 (6–7), Class 175 (5–6), Class 200 (4–5), Class 250 (3–4), Class 300 (2–3), Class 400 (1–2), and Class 500 (below 1 lbs/ft³). Dense, compact items like steel or assembled machinery fall in the lower classes (50–85); bulky, lightweight items like inflatable furniture or ping-pong balls fall in the higher classes (300–500).

Class 50 is the cheapest freight class to ship — it applies to extremely dense shipments (≥ 50 lbs/ft³) that are easy to stack, handle, and store in a trailer. Examples include clean bricks, mortar, and dense metal parts. Class 500 is the most expensive class — it applies to shipments with density below 1 lb/ft³, such as ping-pong balls, gold leaf, or inflatable items that take up enormous trailer space relative to their weight. The spread in carrier rates between Class 50 and Class 500 can be tenfold or greater, which is why accurately calculating density is critical before booking LTL freight.

LTL (Less-than-Truckload) shipping is a freight transportation method where multiple shippers share space in a single truck. Instead of booking an entire truckload, you pay only for the portion of trailer space your shipment occupies. LTL is typically used for shipments between 150 lbs and 10,000 lbs that are too large for parcel carriers (UPS, FedEx) but too small to justify a full truckload. Major LTL carriers in the US include FedEx Freight, Old Dominion, XPO Logistics, Estes Express, and ABF Freight. Every LTL shipment must be assigned an NMFC freight class on the bill of lading.

The density formula for freight class is: Density (lbs/ft³) = Total Weight (lbs) ÷ Volume (ft³). Volume is calculated as: Volume (ft³) = (Length (in) × Width (in) × Height (in)) ÷ 1,728. The constant 1,728 converts cubic inches to cubic feet (12³ = 1,728). For example, a 200 lb shipment in a box measuring 36 × 24 × 24 inches has a volume of (36 × 24 × 24) ÷ 1,728 = 12 ft³, and a density of 200 ÷ 12 = 16.67 lbs/ft³, which falls in freight Class 70 (15–22.5 lbs/ft³).

Yes — freight class is the most direct driver of your base LTL rate. Every carrier publishes a rate tariff that lists a base rate per hundredweight (CWT, meaning per 100 lbs) for each freight class and lane (origin-destination pair). A Class 100 shipment might be priced at $35/CWT on a given lane; the same weight and dimensions reclassified to Class 250 might cost $90/CWT — a 157% increase. Additionally, accessorial charges such as liftgate, inside delivery, and residential surcharges are applied on top of the base class rate. Accurate freight class assignment is therefore essential for getting competitive quotes.

The NMFC (National Motor Freight Classification) is the standardised freight classification system published by the National Motor Freight Traffic Association (NMFTA), a non-profit organisation based in Alexandria, Virginia. First established in 1936 and updated regularly, the NMFC assigns a class number between 50 and 500 to virtually every commodity shipped by truck. In addition to the density-based classes covered by this calculator, the NMFC accounts for four transportation characteristics: density (weight per cubic foot), stowability (ease of loading with other freight), ease of handling, and liability (value density and susceptibility to damage or theft). The official NMFC directory is subscription-based and is the authoritative reference for regulated commodities.

The most effective way to reduce your freight class — and therefore your shipping cost — is to increase the density of your shipment. Practical strategies include: (1) Consolidate packaging — remove excess air space inside boxes, use snugger cartons, and eliminate unnecessary internal void fill. (2) Use a pallet — placing multiple items on a single pallet often reduces the class compared to shipping them individually, because carriers measure the total footprint of the pallet rather than each individual box. (3) Repack into smaller dimensions — halving the height of a shipment can double its density and potentially drop it two or three freight classes. (4) Break into separate shipments — if one item is very light and bulky, consider shipping it separately from denser items so each is classified on its own merits. Always re-measure after repacking and recalculate density before printing your bill of lading.

A freight class chart (also called an NMFC freight class table) is a reference document that maps density ranges to their corresponding NMFC freight classes. The chart has 18 rows — one per class from 50 to 500 — and shows the minimum and maximum density in lbs/ft³ that qualifies a shipment for each class. Carriers and freight brokers use the chart when auditing bills of lading to verify that the declared class matches the shipment's actual weight and dimensions. This calculator implements the complete 18-class density chart, so you can look up any shipment's class instantly without needing a printed reference.