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Density: — lbs/ft³
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Using the Freight Class Calculator
Shipping Less-Than-Truckload (LTL) freight requires an accurate NMFC (National Motor Freight Classification) class to ensure proper pricing. This freight class calculator helps shippers estimate their freight class based primarily on density, which is the most common factor for commodity classification.
To get an accurate result, follow these steps:
- Length, Width, & Height
- Measure the furthest points of your shipment, including pallets or packaging. Use inches for the most accurate calculation.
- Total Weight
- Enter the gross weight of the shipment in pounds (lbs), including the pallet and all packing materials.
- Show Solution Steps
- Enabling this will show you the exact cubic footage and pounds per cubic foot (PCF) used to determine the class.
How Freight Class is Calculated
The NMFTA (National Motor Freight Traffic Association) defines freight classes based on four characteristics: density, stowability, ease of handling, and liability. Most modern shipments are "density-based," meaning as the density of the package increases, the freight class (and usually the rate per hundred pounds) decreases.
The fundamental formula used by our freight class calculator is:
Density (PCF) = Weight (lbs) / [Length × Width × Height (in) / 1728]
- Volume: Calculated in cubic feet by dividing the total cubic inches by 1,728.
- Density: Expressed as Pounds per Cubic Foot (PCF).
- Class Assignment: The PCF is compared against standard NMFC density breaks (ranging from Class 50 for very heavy items to Class 500 for very light, bulky items).
Freight Class Calculation Example
Scenario: You are shipping a pallet of machinery parts that weighs 850 lbs. The pallet dimensions are 48″ long, 40″ wide, and 30″ high.
Step-by-step solution:
- Calculate Cubic Inches: 48 × 40 × 30 = 57,600 cubic inches.
- Convert to Cubic Feet: 57,600 / 1728 = 33.33 cubic feet.
- Calculate Density: 850 lbs / 33.33 ft³ = 25.50 PCF.
- Determine Class: According to the density table, a density of 25.50 PCF falls into Class 65 (range 22.5 to 30 PCF).
Standard Density Table
The following table provides a general guideline for density-based freight classes. Note that specific NMFC codes for your commodity may override these general density rules.
| Density (PCF) | Estimated Class |
|---|---|
| Greater than 50 | 50 |
| 30 to 35 | 60 |
| 15 to 22.5 | 70 |
| 9 to 10.5 | 100 |
| 5 to 6 | 175 |
| Less than 1 | 500 |
Common Questions
What if my item is fragile?
Fragility affects the "Liability" factor of NMFC classification. If an item is highly prone to damage or theft, the NMFC may assign it a higher freight class regardless of its density. Our freight class calculator provides an estimate based on density, but you should always verify with the NMFC book for specific items like electronics or glassware.
Why did my carrier re-class my shipment?
Carriers use "dimensioners" (laser scanners) to verify the exact length, width, height, and weight of every shipment. If your measurements were off by even an inch, or if a piece of shrink wrap was sticking out, it could change the density enough to trigger a re-classification and a price increase (often called a "billing adjustment").
Does the pallet weight count?
Yes. For LTL shipping, the weight of the pallet, crates, and all packaging material must be included in the total weight used for the freight class calculation. Failing to include the 40-50 lbs of a standard wooden pallet is a common cause of weight discrepancies.