Density is the single number that decides most NMFC freight classes, and it is nothing more than weight divided by volume. If you only have inches, multiply length by width by height and divide by 1,728 to get cubic feet first, then divide weight by that figure. The two fields above do the arithmetic for you the moment you type.
Worked example: 500 lbs in 44.4 cubic feet
The calculator loads with a common reference shipment already filled in, so you can see the full path from raw numbers to a class before you touch a single field.
- Inputs: 500 lbs total weight, 44.4 cubic feet of volume. That volume matches a shipment measuring roughly 40 x 48 x 40 inches (40 × 48 × 40 ÷ 1,728 = 44.4 cubic feet), a common pallet footprint with a 40 inch load height.
- Step 1: Divide weight by volume: 500 ÷ 44.4 = 11.26 pounds per cubic foot.
- Step 2: Match 11.26 PCF against the breakpoint table below. It sits inside the 10.5 to 12 PCF band.
- Result: Class 92.5, the same band that covers computers, monitors and similar mid-density electronics.
Change either number above and the result updates instantly using the exact same two steps: divide, then match against the table.
NMFC density breakpoints
This is the same 18-row scale coded into the calculator's classFor() function, reflecting the density-based general commodity scale published in the National Motor Freight Classification.
| Class | Density (PCF) | Typical goods |
|---|---|---|
| 50 | 50+ | Nuts, bolts, bricks |
| 55 | 35 to 50 | Cement, hardwood |
| 60 | 30 to 35 | Car parts, beverages |
| 65 | 22.5 to 30 | Machinery, engines |
| 70 | 15 to 22.5 | Food, wood furniture |
| 77.5 | 13.5 to 15 | Tires, fixtures |
| 85 | 12 to 13.5 | Crated machinery |
| 92.5 | 10.5 to 12 | Computers, electronics |
| 100 | 9 to 10.5 | Wine cases, boat covers |
| 110 | 8 to 9 | Cabinets, artwork |
| 125 | 7 to 8 | Small appliances |
| 150 | 6 to 7 | Auto sheet metal |
| 175 | 5 to 6 | Clothing, couches |
| 200 | 4 to 5 | Packaged mattresses |
| 250 | 3 to 4 | Bamboo furniture |
| 300 | 2 to 3 | Wood cabinets |
| 400 | 1 to 2 | Very low density |
| 500 | Under 1 | Ping pong balls |
What the result actually means
A PCF number by itself is not very useful. What matters is which row it lands in, because that row is the class your rate is built on. Two shipments that weigh the same but occupy different volumes can land three or four classes apart, and that gap alone can double the per-hundred-pound rate. Reading the density figure as "which row am I in" rather than as a standalone statistic is the fastest way to sanity-check a quote before it comes back from the carrier higher than expected.
Keep in mind this tool answers the density question only. Fragile goods, oddly shaped freight, or commodities with a specific NMFC item number can carry a class that does not match the density table at all, no matter how the math above comes out.
Need the full cost picture too?
The Freight Class Calculator adds dimensions, a commodity picker and a ballpark LTL cost range on top of this same density math.