The Freight Class Formula
Freight class for density-based LTL cargo is calculated in four steps:
1. Measure the length, width, and height of each handling unit in inches (including pallet and protrusions).
2. Calculate the total cubic feet: (Length × Width × Height) ÷ 1,728.
3. Weigh the total shipment on a certified scale (including pallet tare weight).
4. Calculate density (PCF): Total Weight in Pounds ÷ Total Volume in Cubic Feet.
Worked Example: Single Loaded Pallet
Consider a pallet shipment with the following verified measurements:
* Dimensions: 48 in (L) × 40 in (W) × 54 in (H)
* Total Gross Weight: 850 lb
Step 1: Calculate cubic volume in inches:
48 × 40 × 54 = 103,680 cubic inches.
Step 2: Convert to cubic feet:
103,680 ÷ 1,728 = 60.0 cubic feet.
Step 3: Calculate density:
850 lb ÷ 60.0 ft³ = 14.17 lb/ft³ (PCF).
Step 4: Look up in the 13-sub density table:
14.17 lb/ft³ falls in the 12 to <15 PCF band, resulting in an estimated Freight Class 85.
Common Mistakes That Cause Carrier Re-Weigh Adjustments
Carriers routinely run shipments through automated dimensioning scanners. The three most common triggers for re-billing are:
* Forgetting pallet height: Measuring carton height instead of total loaded height from floor to top.
* Ignoring overhang: If boxes bulge 2 inches beyond the pallet deck, the scanner measures the widest bulge.
* Underestimating tare weight: Forgetting that a standard wooden GMA pallet weighs 35–45 lb.