LTL Freight Class Calculator (Density Method)
Enter shipment dimensions and total weight to estimate NMFC freight class based on density (lb/ft³).
How to determine freight class
Freight class is one of the most important inputs in LTL (less-than-truckload) shipping. It affects your shipping quote, your invoice, and potential reclassification charges. In many cases, class can be estimated from density: how many pounds your shipment weighs per cubic foot.
This calculator helps you quickly estimate class using shipment dimensions and weight. It’s ideal for budgeting freight costs before booking. Keep in mind: carriers can still adjust class based on packaging, stowability, liability, or special handling.
Inputs you need
- Length, width, and height (inches): size of one shipping unit or pallet.
- Number of units: total count of identical pieces/pallets.
- Total weight (lbs): combined weight of the full shipment.
Formula used in the calculator
The calculator uses a standard density workflow:
- Cubic inches per unit = Length × Width × Height
- Total cubic inches = Cubic inches per unit × Number of units
- Total cubic feet = Total cubic inches ÷ 1,728
- Density (lb/ft³) = Total weight ÷ Total cubic feet
Common density-to-class reference
| Density (lb/ft³) | Estimated Freight Class |
|---|---|
| 50 or greater | Class 50 |
| 35 to < 50 | Class 55 |
| 30 to < 35 | Class 60 |
| 22.5 to < 30 | Class 65 |
| 15 to < 22.5 | Class 70 |
| 13.5 to < 15 | Class 77.5 |
| 12 to < 13.5 | Class 85 |
| 10.5 to < 12 | Class 92.5 |
| 9 to < 10.5 | Class 100 |
| 8 to < 9 | Class 110 |
| 7 to < 8 | Class 125 |
| 6 to < 7 | Class 150 |
| 5 to < 6 | Class 175 |
| 4 to < 5 | Class 200 |
| 3 to < 4 | Class 250 |
| 2 to < 3 | Class 300 |
| 1 to < 2 | Class 400 |
| Less than 1 | Class 500 |
Worked example
Suppose you have 2 pallets, each measuring 48 × 40 × 50 inches, and total shipment weight is 1,000 lbs.
- Per pallet volume = 48 × 40 × 50 = 96,000 in³
- Total volume = 96,000 × 2 = 192,000 in³
- Total cubic feet = 192,000 ÷ 1,728 = 111.11 ft³
- Density = 1,000 ÷ 111.11 = 9.0 lb/ft³
A density of about 9.0 lb/ft³ maps to an estimated Class 100.
Why your invoice class may differ
Density is often the starting point, but NMFC classification can include other characteristics:
- Handling: difficult-to-handle or fragile freight can increase class.
- Liability: risk of theft, damage, or spoilage can affect class.
- Stowability: odd shapes or hazardous materials can change rating.
- NMFC item exceptions: specific commodities may have fixed classes.
Final thoughts
A reliable freight class estimate helps avoid surprises and compare LTL rates more confidently. Use this tool as a quick pre-quote calculator, then verify with your carrier, broker, or NMFC documentation before tendering freight.