What freight class is 40 lb per cubic foot?
Class 55 — sub-provision 12, NMFC density scale effective July 19, 2025.
40 lb/ft³ falls in the 35 to under 50 lb/ft³ band, which rates class 55. On a standard 48 × 40 × 48 in pallet (53.3 ft³) that is about 2,133 lb including the pallet.
How close is 40 lb/ft³ to the next class?
Cheaper class
Class 50 at 50 lb/ft³ — 10 lb/ft³ away (about 533 lb more on the same pallet).
Dearer class
Class 60 below 35 lb/ft³ — 5 lb/ft³ away (losing about 267 lb, or gaining that much cube, tips you over).
Density is total shipment weight divided by total cubic feet, pallet included. Overhang counts: carriers measure the extreme outside dimensions, not the pallet footprint.
What 40 lb/ft³ looks like on real pallets
| Pallet size | Volume | Weight at 40 lb/ft³ |
|---|---|---|
| 48 × 40 × 48 in | 53.3 ft³ | 2,133 lb |
| 48 × 40 × 60 in | 66.7 ft³ | 2,667 lb |
| 48 × 40 × 72 in | 80 ft³ | 3,200 lb |
| 48 × 48 × 48 in | 64 ft³ | 2,560 lb |
Taller pallets need proportionally more weight to hold the same density — which is why stacking higher without adding weight is what most often causes a reclass.
The full density scale
| Sub | Density (lb/ft³) | Class |
|---|---|---|
| 1 | Less than 1 | 400 |
| 2 | 1 to under 2 | 300 |
| 3 | 2 to under 4 | 250 |
| 4 | 4 to under 6 | 175 |
| 5 | 6 to under 8 | 125 |
| 6 | 8 to under 10 | 100 |
| 7 | 10 to under 12 | 92.5 |
| 8 | 12 to under 15 | 85 |
| 9 | 15 to under 22.5 | 70 |
| 10 | 22.5 to under 30 | 65 |
| 11 | 30 to under 35 | 60 |
| 12 | 35 to under 50 | 55 ← you are here |
| 13 | 50 or more | 50 |
Thirteen sub-provisions — not eighteen. The current scale never produces class 77.5, 110, 150, 200 or 500 from density; those apply only to commodity-specific NMFC items.
Not sure of your density? The freight class calculator works it out from dimensions and weight, or read what class 55 means in full.