Step 1 — measure the handling unit

Length, width and height in inches, taken on the outside of the loaded pallet. That means including the pallet itself, the shrink wrap, any overhang past the pallet edge, and anything strapped on top. Weigh it gross.

This is the step people get wrong, and it is the only step that costs money. Carriers run dimensioning scanners at the terminal. Whatever the scanner reads is what you get rated on.

Step 2 — convert to cubic feet

cubic feet = (L × W × H) ÷ 1728

1728 is the number of cubic inches in a cubic foot. If you have several identical pallets, multiply by the count. If they differ, do each one and add the results.

Working in centimetres, divide each dimension by 2.54 first. Kilos convert to pounds at 2.20462.

Step 3 — divide weight by volume

density (pcf) = total pounds ÷ total cubic feet

For a mixed shipment, pool everything: all weight over all volume, one density for the tender. That is how the carrier rates it.

Step 4 — read the band

Match the density against the NMFC density scale. Thirteen bands since 19 July 2025. Bands are inclusive at the lower number: exactly 15.00 pcf is class 70, not 85.

Skip the arithmetic and use the calculator →

Worked example: one pallet

A 48 × 40 inch pallet stacked to 48 inches, 800 lb gross.

48 × 40 × 48 = 92,160 cubic inches
92,160 ÷ 1728 = 53.33 cubic feet
800 ÷ 53.33 = 15.00 pcf
15.00 falls in the 15 – 22.5 band → class 70

Worked example: mixed pallets

Two pallets at 48 × 40 × 40 inches, 500 lb each, plus one at 48 × 48 × 60 inches, 300 lb.

First pair: 76,800 ÷ 1728 = 44.44 cu ft each, 88.89 cu ft total
Third: 138,240 ÷ 1728 = 80.00 cu ft
Total volume 168.89 cu ft, total weight 1,300 lb
1,300 ÷ 168.89 = 7.70 pcf → class 125

Note what the tall light pallet did: it contributed 47% of the volume and 23% of the weight, dragging the whole shipment down two bands. Splitting it onto a separate BOL would rate the dense freight far better.

The four mistakes that cost the most. Rounding the height down instead of measuring it. Forgetting the pallet weight, typically 35–50 lb each. Ignoring overhang. Using a chart with 18 rows — that is not the NMFC density scale, and it will hand you class 500 or 77.5, neither of which any current band produces.

When the arithmetic is not the answer

Density gives the class for commodities that classify by density. Where the NMFC item carries a fixed class, or where stowability, handling or liability dominate, the class comes from the item number instead. See freight class codes.

How to calculate freight class