About FreightPrep
How the calculator works
The calculator packs your boxes onto a pallet using grid layer packing: it tries both carton orientations on the pallet base (length-by-width and width-by-length) and keeps whichever fits more boxes per layer. The number of layers is capped by the pallet standard’s maximum stack height, so a pallet never exceeds a safe, shippable height. Each pallet’s total weight includes the pallet itself (deck weight), not just the boxes on it — that combined weight and the pallet’s outer dimensions are what determine density and freight class.
NMFC density scale (effective 2025-07-19)
Freight class here is calculated purely from density (weight ÷ cubic feet), using the NMFC 13-subprovision full-density scale below.
| Density (lbs/ft³) | Freight class |
|---|---|
| < 1 | 400 |
| 1 – 2 | 300 |
| 2 – 4 | 250 |
| 4 – 6 | 175 |
| 6 – 8 | 125 |
| 8 – 10 | 100 |
| 10 – 12 | 92.5 |
| 12 – 15 | 85 |
| 15 – 22.5 | 70 |
| 22.5 – 30 | 65 |
| 30 – 35 | 60 |
| 35 – 50 | 55 |
| ≥ 50 | 50 |
Disclaimer
This tool provides estimates only. Final freight class and rates are set by the carrier and the National Motor Freight Traffic Association (NMFTA), not by this calculator. Always verify measurements and weight at pickup. Freight class here is density-based only — the specific commodity’s NMFC item number may override the density-based class shown here.