Freight Class Calculator

Freight class is most often driven by density. Multiply length × width × height in inches, divide by 1,728 to get cubic feet per piece, then multiply by the piece count. Divide the shipment's total weight in pounds by that cubic footage to get density in pounds per cubic foot, then read the density against the NMFC density brackets — the denser the freight, the lower the class and generally the lower the rate.

Density (lb/ft³) = total weight in pounds ÷ total cubic feet, where total cubic feet = (length × width × height in inches ÷ 1,728) × number of pieces. Always measure the outside of the packaged, palletised freight — including the pallet itself and any overhang — because that is what the carrier measures on the dock.

No, and this is the most common and most expensive misunderstanding. The NMFC classifies commodities on four factors: density, stowability, handling, and liability. Many commodities are assigned a fixed class under a named NMFC item regardless of how dense the shipment is, and others use brackets specific to that item number. A density calculation is a reliable estimate only when a density-based item genuinely applies, so confirm the actual NMFC item and sub-number before booking.

Effective July 19, 2025, the NMFTA standardized the full density scale at 13 tiers. Under the current scale, less than 1 lb/ft³ is class 400, 1–2 is 300, 2–4 is 250, 4–6 is 175, 6–8 is 125, 8–10 is 100, 10–12 is 92.5, 12–15 is 85, 15–22.5 is 70, 22.5–30 is 65, 30–35 is 60, 35–50 is 55, and 50+ is class 50. Older 18-tier density tables — the ones showing sub-classes like 77.5 at 13.5 lb/ft³ or 110 at 8 lb/ft³ — are no longer the standard scale, and many calculators online still publish them.

The NMFC class ladder runs from 50 to 500 — historically 18 classes: 50, 55, 60, 65, 70, 77.5, 85, 92.5, 100, 110, 125, 150, 175, 200, 250, 300, 400 and 500. Class 50 is the densest and cheapest to ship; class 500 the lightest and most expensive per pound. Since July 19, 2025, the standard density scale maps to 13 of those classes (50 through 400), though commodity-specific NMFC items can still carry other classes.

The carrier will typically reweigh or re-measure the shipment on the dock, reclassify it, and issue a corrected invoice for the difference — often with an inspection or reclassification fee on top. Because the correction arrives after delivery, it usually lands as an unexpected charge weeks later, which is why getting class right at the point of quoting matters more than fixing it afterwards.

No. Freight class is an NMFC concept used in LTL trucking, and dimensional weight is a parcel-carrier concept. Both penalise light, bulky freight, but they are calculated differently and are not interchangeable. An LTL carrier prices from class and actual weight, not from a dimensional weight figure.