What Is a Shipping Class?
A shipping class is the classification code assigned to a freight shipment under the National Motor Freight Classification (NMFC) system. Used by LTL (Less-Than-Truckload) carriers throughout North America, shipping classes range from Class 50 to Class 500, with each class representing a different category of freight based on density, handling characteristics, stowability, and liability risk.
When you book an LTL shipment, the carrier uses your declared shipping class — combined with shipment weight and origin/destination — to calculate the freight rate. This makes accurate shipping class calculation one of the most important tasks in freight management. Our free shipping class calculator makes this process fast, easy, and accurate.
The concept of shipping class exists to standardize how carriers price freight that varies widely in size, weight, fragility, and value. Without a standard classification system, pricing would be inconsistent and difficult to compare across carriers. The NMFC shipping class system solves this by providing a universal language for freight pricing across the U.S. trucking industry.
Shipping Class vs. Freight Class
The terms shipping class and freight class are completely interchangeable. Both refer to the same NMFC classification number — the standardized code that carriers use to price LTL shipments. You may hear "shipping class" more commonly in e-commerce and retail contexts, while "freight class" is the preferred term in traditional logistics and trucking.
Similarly, a freight shipping class calculator and a shipping class calculator perform the same function: they help you determine which NMFC class your shipment belongs to based on its physical characteristics. Our tool serves both purposes and is often used interchangeably as a freight class calculator and a shipping class calculator.
How to Determine Your Shipping Class
The most common method for determining shipping class is the density method. Here's how to calculate it step by step:
- Measure your freight: Record the length, width, and height of your shipment as it will be shipped (including pallets and packaging).
- Calculate cubic footage: Multiply length × width × height, then divide by 1,728 if your measurements are in inches.
- Weigh your freight: Record the total weight including all packaging and pallets.
- Calculate density: Divide total weight (lbs) by volume (cu ft).
- Look up your class: Match your density value to the NMFC density-to-class table, or use our class calculator for shipping to do it automatically.
Our online freight class calculator handles all these calculations instantly. Just enter your dimensions and weight, and the tool outputs your shipping class in seconds.
📌 Important: Always measure the full pallet dimensions, not just the product. The pallet footprint (typically 48" × 40") and total stacked height must be included in your shipping class calculation to avoid carrier reclassification.
Shipping Class Reference Table
| Shipping Class | Density (lbs/cu ft) | Example Items |
|---|---|---|
| Class 50 | ≥ 50 | Fitted metal parts, steel castings |
| Class 55 | 35–50 | Bricks, cement blocks, tile |
| Class 60 | 30–35 | Car parts, canned food, tools |
| Class 65 | 22.5–30 | Bottled drinks, auto accessories |
| Class 70 | 15–22.5 | Food products, small appliances |
| Class 77.5 | 13.5–15 | Tires, fixtures |
| Class 85 | 12–13.5 | Crated machinery, stoves |
| Class 92.5 | 10.5–12 | Computers, monitors |
| Class 100 | 9–10.5 | Wine cases, boat covers |
| Class 110 | 8–9 | Cabinets, framed art |
| Class 125 | 7–8 | Electric instruments |
| Class 150 | 6–7 | Auto sheet metal |
| Class 175 | 5–6 | Clothing, sofas |
| Class 200 | 4–5 | Aircraft parts, aluminum tables |
| Class 250 | 3–4 | Mattresses, plasma TVs |
| Class 300 | 2–3 | Crated tables, wood cabinets |
| Class 400 | 1–2 | Ping pong balls, antlers |
| Class 500 | < 1 | Bags of air, gold dust |
How Shipping Class Impacts Your Rates
Your shipping class is one of the primary drivers of LTL freight rates. Carriers apply a class-based multiplier to the base rate, meaning that a higher shipping class translates directly to higher per-hundredweight (CWT) rates. The relationship between shipping class and cost is not always linear — some classes have significantly higher rates than adjacent classes due to the handling challenges they present.
As a rule of thumb, moving from Class 70 to Class 100 for the same weight shipment can increase your freight bill by 40–60%. Moving from Class 100 to Class 175 might double or triple your rate. This is why it pays to use an accurate shipping class calculator before booking freight — and why packaging optimization to achieve a lower shipping class can yield significant savings.
Additionally, carriers sometimes reclassify freight after pickup. This happens when the carrier's measurement of your freight differs from what you declared. Using our accurate class calculator for shipping ensures your declared dimensions match the actual freight, reducing the risk of expensive post-delivery reclassification charges.
Essential Tips for Accurate Classification
- Always include the pallet: Pallet weight and dimensions must be included in your shipping class calculation.
- Measure before you book: Never estimate dimensions. Use a tape measure and record accurate values before calculating your shipping class.
- Account for overhang: If your freight overhangs the pallet edge, measure to the furthest point of overhang.
- Use actual weight, not estimated weight: Weigh your complete shipment, including pallet and stretch wrap, before calculating density.
- Check NMFC item numbers: For specialty commodities, the NMFC may assign a fixed class based on item number rather than density. Verify with your carrier or freight broker.
- Update your class as packaging changes: If you change packaging, box sizes, or consolidation methods, recalculate your shipping class to ensure it's still accurate.
Shipping Class by Industry
Different industries tend to have predictable shipping class ranges. Understanding your industry's typical freight class helps you spot errors and plan freight costs more accurately. Here's a guide to shipping class by common shipping categories:
Manufacturing & Industrial
Metal parts, castings, and machined components are among the densest freight. These items frequently qualify for Class 50 or Class 55 — the cheapest shipping classes available. A solid steel casting measuring 24" × 24" × 12" at 800 lbs would have a density of over 60 lbs/cu ft, making it Class 50. Manufacturers shipping heavy machinery components benefit enormously from accurate shipping class calculation because even small misclassifications on high-value freight can add hundreds of dollars per shipment.
Food & Beverage
Canned goods, bottled beverages, and packaged foods generally fall between Class 55 and Class 85. The wide range reflects the diversity of packaging types. A pallet of 24 cases of bottled water is dense and compact — likely Class 55–65. But a pallet of large cereal boxes is bulky and light, potentially pushing into Class 92.5 or Class 100. Always calculate by actual pallet dimensions rather than assuming your product falls in a standard class.
Retail & E-Commerce
Consumer goods shipped in standard retail packaging typically fall in the Class 85 to Class 150 range. Electronics such as laptops and monitors often fall into Class 92.5. Clothing and textiles frequently land at Class 150–175 due to their low density when packaged in boxes. Home décor and seasonal items can vary widely. E-commerce merchants shipping LTL regularly should use our shipping class calculator for every new SKU to build an accurate freight cost model.
Furniture & Home Goods
Furniture is one of the most challenging freight categories for shipping class calculation. Assembled furniture with hollow frames and cushions can easily reach Class 200 to Class 300. Flat-pack and ready-to-assemble furniture, however, ships much more efficiently at Class 85 to Class 150. Many furniture brands have shifted to flat-pack specifically to reduce shipping class and freight costs. Mattresses, despite being relatively heavy, are extremely bulky and often classified at Class 250.
Automotive
Automotive parts span almost the entire shipping class spectrum. Small, dense metal parts (brackets, fasteners, castings) may qualify for Class 50. Larger body panels, hoods, and bumpers — while still metal — are bulky and lightweight relative to their size, often landing at Class 150 to Class 200. Tires typically fall at Class 77.5 when properly packaged. Always measure the actual packaged dimensions rather than relying on product weight alone when calculating shipping class for automotive freight.
How to Avoid Freight Reclassification
Freight reclassification — when a carrier changes your declared shipping class after pickup — is one of the most frustrating and costly problems in LTL shipping. Reclassification charges can add 30%–200% to your expected freight bill, and they're often issued weeks after delivery, making budgeting difficult.
The best defense is an accurate shipping class declaration in the first place. Here's how to ensure your shipping class calculator inputs are correct:
- Measure the pallet, not the product: Always measure to the outermost edge of your packaged shipment, including stretch wrap.
- Use actual scale weight: Never estimate. Even being off by 10–20 lbs can push density across a class boundary for lighter shipments.
- Account for irregular shapes: Measure to the longest/widest/tallest point, even if the product doesn't fill that space.
- Declare stacked height accurately: If items are stacked on a pallet, measure the total height including the pallet (typically 5–6 inches).
- Verify NMFC item numbers: For regulated commodities, the NMFC assigns fixed classes independent of density. Ask your carrier if your commodity has a fixed NMFC item number.
When in doubt, it's better to slightly over-declare your shipping class than under-declare. Reclassification fees (including re-weighing charges) can easily exceed the savings from a misclassified lower class.