Freight Class Calculator
Optional: enter your LTL rate per 100 lbs to estimate shipping cost.
Enter Shipment Dimensions
Enter your shipment length, width, height, and weight to calculate your NMFC freight class and shipping density.
Four Factors That Determine Freight Class
1. Density (Primary)
Weight in pounds per cubic foot (lbs/ft³). Lower density means a higher class number and higher shipping cost. This is the primary factor for most general commodities and the basis of this calculator.
2. Stowability
Can the freight be safely loaded and stacked with other cargo? Hazardous materials, oversized items, or irregularly shaped goods that cannot be stowed with other freight receive higher classes regardless of density.
3. Handling
Does the freight require special handling — cranes, refrigeration, hazmat protocols, or extra labor? Freight requiring special handling is classified higher than standard palletized goods of similar density.
4. Liability
What is the risk of damage, theft, or perishability? High-value electronics, fragile goods, and perishables may be classified by commodity-specific NMFC item number rather than density, often resulting in higher classes.
How to Use the Freight Class Calculator
Enter Shipment Dimensions and Weight
Input the length, width, and height of your shipment in inches (or centimeters if using metric). Enter the total weight in pounds (or kilograms). Use standard pallet presets — 48×40, 48×48, 42×42, or 36×36 inches — for quick entry of common pallet sizes. For multiple different items in one shipment, click 'Add Line Item' to enter each piece type separately.
Review Your Freight Class and Density
The calculator instantly displays your NMFC freight class (50–500) as the primary result, along with your shipment density in lbs/ft³, total volume in cubic feet, and total weight in pounds. The visual spectrum bar shows where your density falls on the cost scale — further right (greener) means lower class and cheaper shipping.
Check the Optimization Tip and Cost Estimate
If applicable, review the optimization tip showing how many pounds to add to drop to the next lower (cheaper) freight class. To estimate shipping cost, enter your carrier's CWT rate (rate per 100 lbs) in the CWT field. Enable 'Show step-by-step calculation' to see the full volume, density, and class determination math.
Export or Consult the NMFC Table
Download your results as a CSV file or print a summary for your shipping records. Expand the full NMFC Class Reference Table to browse all 18 freight classes with density ranges, cost levels, and example commodities. Your calculated class is highlighted in the table for easy reference. Always verify critical shipments with your carrier or freight broker.
Frequently Asked Questions
What is the difference between freight class and dimensional weight?
Freight class and dimensional weight are two completely separate pricing systems used by different shipping modes. Freight class (NMFC) is used exclusively for LTL (Less-than-Truckload) truck shipping in the US. It's based on density, stowability, handling, and liability — not just size. Dimensional weight (dim weight) is used by parcel carriers like UPS, FedEx, and USPS, and by air freight. It's calculated as (L × W × H) ÷ a divisor (usually 139 for domestic US). If your package's dimensional weight exceeds its actual weight, you're billed on dimensional weight. For LTL shipments, freight class — not dim weight — determines your rate. Full truckload (FTL) pricing is based on lane and mileage, neither class nor dim weight.
Why is my freight class important for LTL shipping?
In LTL shipping, multiple shippers share space on one trailer. Carriers need a standardized way to price that shared space fairly — that system is NMFC freight class. Your freight class directly determines your base rate per hundredweight ($/cwt). Carriers publish class-specific tariff tables, so Class 50 freight might cost $10/cwt while Class 200 freight costs $80/cwt on the same lane. Misclassifying your freight — even unintentionally — triggers reclassification fees when carriers physically inspect shipments. These fees are typically 20–30% surcharges added to the corrected rate, and they're almost impossible to dispute. Accurate classification protects you from billing surprises and ensures your shipment is handled appropriately.
What does it mean if my freight class is high (300, 400, or 500)?
A high freight class number (300–500) means your shipment has very low density — it takes up a lot of space relative to its weight. Carriers charge more for these shipments because they fill trailer space without contributing much to the overall weight capacity of the load. Class 300 freight (density 2–3 lbs/ft³) includes assembled wood furniture and cabinets. Class 400 (1–2 lbs/ft³) includes deer antlers and inflatable items. Class 500 (under 1 lb/ft³) is the most expensive and includes items like ping pong balls and large empty boxes. If your freight consistently falls into high classes, consider whether denser packaging, consolidation, or repackaging could improve your class and lower shipping costs.
Can I reduce my freight class to save money?
Yes — since density is the primary driver of freight class, increasing the density of your shipment moves it into a lower (cheaper) class. Practical strategies include: using smaller, tighter packaging to reduce volume (while keeping weight the same, density increases); consolidating multiple smaller packages into one denser pallet; removing excess packaging materials like air pillows or foam padding where safe; palletizing items that would otherwise ship as individual pieces; and reconsidering the shipment mode — very large or lightweight items might be cheaper as FTL even if the volume doesn't fill a full trailer. The 'Optimization Tip' in this calculator shows exactly how many pounds you'd need to add (or how much volume to reduce) to drop to the next lower class.
What is CWT and how is the cost estimate calculated?
CWT stands for hundredweight — it means 100 pounds. LTL carriers quote freight rates in dollars per hundredweight ($/cwt) based on freight class and lane (origin-destination pair). To estimate your shipping cost, the formula is: Estimated Cost = (Total Weight in lbs ÷ 100) × Rate per CWT. For example, if you're shipping 500 lbs at a rate of $15.50/cwt, your estimate is (500 ÷ 100) × $15.50 = $77.50. Note that actual LTL rates vary significantly by carrier, lane, volume commitment, and contract. The CWT rates in this calculator are estimates only. Always request a formal quote from carriers or freight brokers for accurate pricing.
Does this calculator apply to shipments outside the United States?
The NMFC freight class system is specific to LTL trucking in the United States and Canada. It does not apply to ocean freight (which uses CBM — cubic meters — and commodity codes), air freight (which uses dimensional weight pricing), or international road freight in Europe or other regions (which have their own classification systems). If you're shipping internationally, consult with a freight forwarder for the appropriate classification system. This calculator is optimized for US domestic LTL shipments following NMFTA standards. For Canadian shipments, many carriers accept NMFC classification, but verify with your carrier. The metric unit option in this tool converts cm/kg inputs to lbs/ft³ for NMFC lookup.