LTL Shipping Freight Class Breakpoints and PCF Density Equations
Less-Than-Truckload (LTL) shipping rates in North America are regulated by freight classes. Sizing is governed by the National Motor Freight Traffic Association (NMFTA) using density (Pounds per Cubic Foot, PCF).
1. Sizing LTL Freight Class via Density (PCF)
LTL cargo is classified into one of 18 standard freight classes (Class 50 to Class 500). Heavier, dense commodities (like iron castings or bricks) fall into low classes (Class 50), which carry lower shipping rates. Light, fragile, and bulky items (like cushions or boxes of ping-pong balls) fall into high classes (Class 500), which are more expensive to ship.
2. The PCF Density Calculation
Density represents the weight relative to the volume occupied by the shipment. The formula for density in pounds per cubic foot is:
- Volume (cu ft) = (Length (in) × Width (in) × Height (in)) ÷ (1,728)
- Density (PCF) = (Weight (lbs)) ÷ (Volume (cu ft))
- Note: Always measure to the outermost edges of the shipment, including pallets, skids, or protective packaging, to ensure correct billing.
3. Worked Example
Worked Example: Palletized Industrial Pumps
A shipment has a packaged pallet weight of 450 lbs, measuring 48" long, 40" wide, and 36" high:
Volume = (48 × 40 × 36) ÷ (1,728) = 40 cu ft
Density = (450 lbs) ÷ (40 cu ft) = 11.25 PCF
Looking at standard NMFC density charts, a density of 11.25 PCF maps to **Class 92.5** (which covers densities from 10.5 to 12 PCF).
4. Standard LTL Density Breakpoints Reference Chart
| Density Range (PCF) | Standard Freight Class | Cargo Type Example |
|---|---|---|
| Over 50 PCF | Class 50 | Steel bolts, nuts, heavy metal castings |
| 15 to 22.5 PCF | Class 70 | Car parts, machinery, solid wood panels |
| 10.5 to 12 PCF | Class 92.5 | Palletized industrial pumps, equipment |
| 6 to 7 PCF | Class 150 | Boxed furniture, monitors, plastic panels |
| Under 1 PCF | Class 500 | Ping-pong balls, loose foam packaging |