Calculate NMFC freight class, density, and estimated shipping cost for LTL shipments
Freight class is the backbone of Less-than-Truckload (LTL) shipping pricing in the United States. Every shipment that moves via LTL carrier — where multiple shippers share space on a single trailer — must be assigned an NMFC (National Motor Freight Classification) class number. This class, established by the National Motor Freight Traffic Association (NMFTA), determines how much you pay per hundred pounds to ship your cargo. Getting the class right isn't just about accuracy — misclassification can trigger costly reclassification fees from carriers, often 20–30% surcharges added to your freight bill after inspection. Our Freight Class Calculator uses the complete 18-class NMFC density table to instantly determine your freight class from just four inputs: length, width, height, and weight. Unlike many online tools that only support 13 classes, this calculator includes all 18 official NMFC classes — including classes 77.5, 110, 150, and 200 — ensuring you get the most accurate density-based classification possible. The primary determinant of freight class is density: the ratio of weight to volume, expressed in pounds per cubic foot (lbs/ft³). Dense, compact shipments like steel, bricks, or hardwood flooring earn low class numbers (Class 50–60) and cost the least to ship per pound. Light, bulky items like ping pong balls, large empty boxes, or inflatable toys earn high class numbers (Class 400–500) and cost the most because they consume trailer space disproportionate to their weight. Who needs a freight class calculator? Anyone shipping via LTL — small businesses, e-commerce sellers, manufacturers, wholesalers, and logistics coordinators. Whether you're shipping pallets of bottled beverages (typically Class 65), crated machinery (Class 85), or furniture (Class 175–250), knowing your freight class before booking prevents billing surprises and helps you compare carrier quotes accurately. Beyond basic class determination, this tool also calculates estimated shipping costs using CWT (hundredweight) rates — the standard LTL pricing metric. Enter a rate per hundredweight (cost per 100 lbs) to get a rough cost estimate. You can also add multiple line items for mixed shipments, apply standard pallet dimension presets, toggle between imperial (inches/lbs) and metric (cm/kg) units, and view a step-by-step calculation breakdown showing exactly how density and class were determined. An important note: freight class is based primarily on density, but NMFTA also considers three additional factors — stowability (can it be safely stacked with other freight?), handling (does it require special equipment?), and liability (is it high-value or fragile?). This calculator provides density-based classification, which is correct for the vast majority of general commodities. For specialized, hazardous, or unusually shaped freight, consult an NMFTA ClassIT classification or freight broker. New classification standards from NMFTA went into effect on July 19, 2025. While the density-based table remains the standard for most LTL shipments, NMFTA periodically updates commodity-specific classifications. Always verify critical shipments against current NMFC tariffs or with your carrier.
Understanding Freight Class
What Is Freight Class?
Freight class is a standardized number assigned to LTL shipments under the National Motor Freight Classification (NMFC) system, governed by the National Motor Freight Traffic Association (NMFTA). There are 18 official freight classes ranging from Class 50 to Class 500. The lower the class number, the denser and easier to handle the freight — and the lower the shipping cost per pound. Class 50 freight (density ≥ 50 lbs/ft³) represents the cheapest, most efficient cargo to ship: dense, durable items like steel, brick, and concrete that pack tightly and require no special handling. Class 500 freight (density < 1 lb/ft³) represents the most expensive: ultra-light, space-consuming items like ping pong balls that take up enormous trailer space relative to their weight. Every LTL carrier uses freight class as the primary pricing variable — it's the universal language of LTL shipping.
How Is Freight Class Calculated?
Freight class is determined primarily by density, which is calculated in three steps. First, compute the volume in cubic feet: multiply length × width × height (in inches) and divide by 1,728 (since 12³ = 1,728 cubic inches per cubic foot). For multiple identical pieces, multiply by quantity before dividing. Second, calculate density in lbs/ft³: divide the total weight in pounds by the total volume in cubic feet. Third, look up the freight class in the NMFC density table: a density of 50+ lbs/ft³ gives Class 50, 35–49.99 gives Class 55, down to less than 1 lb/ft³ for Class 500. In metric units, volume is computed in cubic meters (cm³ ÷ 1,000,000), density in kg/m³, then converted to lbs/ft³ by multiplying by 0.0624279 for NMFC lookup. CWT cost is estimated as (total weight ÷ 100) × rate per hundredweight.
Why Does Freight Class Matter?
Freight class is the single most important factor in LTL pricing. Carriers quote rates based on freight class and lane (origin to destination). A one-class error can increase your freight bill by 10–30%. Declaring the wrong class — intentionally or by mistake — leads to reclassification fees when carriers physically inspect and re-weigh shipments. These fees can equal or exceed the original freight charge. Beyond cost, accurate class declarations ensure proper handling: fragile or oversized cargo needs appropriate routing and stacking arrangements. For importers and exporters, freight class also affects insurance calculations and customs documentation. For businesses shipping regularly, even small class improvements (e.g., optimizing packaging to achieve Class 65 instead of Class 70) compound into significant annual savings across hundreds of shipments.
Limitations of Density-Based Classification
This calculator provides density-based freight classification, which is the standard method for most general commodities. However, NMFTA's complete classification system also considers three non-density factors: stowability (whether freight can be safely loaded with other cargo — hazmat, oversized, or oddly shaped items may be classified higher regardless of density), handling (freight requiring special equipment like cranes, temperature control, or extra labor earns higher classes), and liability (high-value goods prone to theft or damage, such as jewelry, electronics, or perishables, are classified by commodity rather than density alone). Some commodities have fixed NMFC item numbers that override density-based class. Always verify class with your carrier or freight broker for specialized cargo. Results from this calculator are estimates — only NMFTA's ClassIT tool and official NMFC tariffs are definitive.
Formulas
Converts a package's dimensions in inches to cubic feet. 1,728 is 12³ — the number of cubic inches in one cubic foot.
Calculates the weight per unit volume. This density value is looked up in the NMFC class table to determine freight class.
CWT stands for hundredweight (100 lbs). LTL carriers quote rates in dollars per CWT based on freight class and lane.
Reference Tables
NMFC Freight Class Density Table (All 18 Classes)
| Class | Density (lbs/ft³) | Cost Level | Typical Commodities |
|---|---|---|---|
| 50 | ≥ 50 | Lowest | Steel coils, bricks, concrete blocks |
| 55 | 35–49.99 | Very Low | Cement, mortar, hardwood flooring |
| 60 | 30–34.99 | Low | Car parts, granite, glass |
| 65 | 22.5–29.99 | Low-Medium | Bottled beverages, car accessories |
| 70 | 15–22.49 | Medium | Auto engines, forklifts, metal castings |
| 77.5 | 13.5–14.99 | Medium | Tires, bathroom fixtures, food items |
| 85 | 12–13.49 | Medium-High | Crated machinery, appliances |
| 92.5 | 10.5–11.99 | Medium-High | Computers, monitors, electronics |
| 100 | 9–10.49 | High | Boat covers, canvas, leather |
| 110 | 8–8.99 | High | Cabinets, framed artwork |
| 125 | 7–7.99 | High | Small appliances, displays |
| 150 | 6–6.99 | Very High | Auto sheet metal, mattresses |
| 175 | 5–5.99 | Very High | Clothing, stuffed furniture |
| 200 | 4–4.99 | Very High | Aircraft parts, sheet metal |
| 250 | 3–3.99 | Extremely High | Bamboo furniture, plasma TVs |
| 300 | 2–2.99 | Extremely High | Wood cabinets, assembled furniture |
| 400 | 1–1.99 | Extremely High | Deer antlers, inflatable toys |
| 500 | < 1 | Highest | Ping pong balls, large empty boxes |
Standard Pallet Sizes
| Name | Dimensions (in) | Industry |
|---|---|---|
| GMA Pallet | 48 × 40 | Most common US/Canada standard |
| Square 48 | 48 × 48 | Drums, barrels, chemical industry |
| Square 42 | 42 × 42 | Telecom, paint industry |
| Half Pallet | 36 × 36 | Retail displays, small loads |
| Euro Pallet | 47.24 × 31.50 (1200×800mm) | European standard |
Worked Examples
Standard GMA Pallet Shipment
Calculate volume: (48 × 40 × 48) ÷ 1,728 = 92,160 ÷ 1,728 = 53.33 ft³
Calculate density: 500 ÷ 53.33 = 9.38 lbs/ft³
Look up in NMFC table: 9–10.49 lbs/ft³ = Class 100
Freight Class = 100
Heavy Machine Part on Half Pallet
Calculate volume: (36 × 36 × 24) ÷ 1,728 = 31,104 ÷ 1,728 = 18 ft³
Calculate density: 400 ÷ 18 = 22.22 lbs/ft³
Look up in NMFC table: 15–22.49 lbs/ft³ = Class 70
Estimated cost: (400 ÷ 100) × $18 = $72
Lightweight Furniture Shipment
Calculate volume: (48 × 18 × 72) ÷ 1,728 = 62,208 ÷ 1,728 = 36 ft³
Calculate density: 85 ÷ 36 = 2.36 lbs/ft³
Look up in NMFC table: 2–2.99 lbs/ft³ = Class 300
Freight Class = 300 — very expensive to ship LTL
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.