Freight Class Calculator

Density (lbs per cubic foot) = Total weight ÷ Volume in cubic feet, where volume = (Length × Width × Height in inches) ÷ 1,728. The density is then matched to an NMFC freight class — denser shipments get a lower class number (cheaper to ship), lighter/bulkier shipments get a higher class number (more expensive).

The National Motor Freight Classification (NMFC) system assigns LTL (less-than-truckload) shipments one of 18 standard classes, from Class 50 (densest, cheapest) to Class 500 (least dense, most expensive), used by carriers to price freight. Classes 50 and 55 were newly added in 2025/2026 to reward especially dense shipments with lower rates.

No — density is the primary factor and what this calculator estimates from, but the official NMFC classification also considers stowability, handling difficulty, and liability (fragility/value) for certain commodities, which can shift the official class up or down from the pure density estimate. Always confirm the exact NMFC code for regulated or unusual freight with your carrier.

Denser freight takes up less trailer space per pound, so carriers can move more weight per truck — lower classes (denser) get lower per-hundredweight rates, while higher classes (bulkier, less dense) cost more per pound to account for the wasted trailer space.