By Stephen Milner · UtilityForge · Last reviewed: May 2026
LTL (less-than-truckload) carriers in North America price shipments using a standardized system called NMFC, which stands for National Motor Freight Classification. The NMFC is published and maintained by the National Motor Freight Traffic Association (NMFTA, nmfta.org). Each shipment is assigned a class number between 50 and 500. Lower classes are cheaper to ship. Higher classes cost more per pound.
A freight class calculator takes your shipment's dimensions and weight, computes the density in pounds per cubic foot, and maps that to one of 18 standard classes. Knowing your class before you book means you get accurate quotes upfront. You avoid discovering a reclassification fee after delivery, which can run hundreds of dollars above your original rate.
This calculator is for anyone moving freight via LTL carriers: e-commerce sellers shipping large goods to customers or fulfillment centers, small business owners booking occasional pallet shipments, logistics coordinators managing regular freight programs, and freight brokers double-checking shipper-provided classifications before tendering a load.
If you have ever received a freight invoice with a line item labeled "reclassification" or "inspection adjustment," this tool addresses exactly that problem.
The core formula is straightforward. Volume in cubic feet equals length times width times height in inches, divided by 1,728 to convert cubic inches to cubic feet. Density in pounds per cubic foot (PCF) equals gross weight in pounds divided by that volume.
Example: a shipment measuring 48 x 40 x 36 inches and weighing 500 lbs has a volume of 40 cubic feet and a density of 12.5 PCF, placing it in Class 85.
Always use outer dimensions after packaging. If the shipment sits on a pallet, include the pallet footprint (typically 48 x 40 inches) in your length and width, and add pallet weight (usually 35 to 50 lbs for a standard wood pallet) to your gross weight.
Density drives classification for most general freight, but the NMFC system officially weighs four characteristics when assigning a class.
Density. Weight per cubic foot. Higher density means a lower class and cheaper rates. This is the only factor this calculator uses, which covers the large majority of commercial shipments.
Stowability. Whether the freight can be stacked, loaded around, or must remain upright. Odd-shaped items, hazardous materials, and goods that cannot be stacked rate higher.
Handling. How much carrier labor the shipment requires. Fragile goods, items needing special equipment, and unusually shaped pieces cost more to move through a terminal.
Liability. The risk the carrier takes on if freight is damaged or stolen. High-value electronics, perishables, and regulated materials carry higher liability, reflected in the class.
For general manufactured goods and commodity freight, density alone determines the class. The other three factors primarily apply to specialty and regulated shipments. In those cases, the carrier or broker will advise you.
Knowing where typical products fall helps you sanity-check a calculator result and catch measurement errors before booking.
Class 50 to 65: dense, inexpensive to ship. Heavy machinery, cast iron parts, steel structural components, sand, aggregate, rock salt, bottled beverages, canned goods, and cement products. These goods pack significant weight into a small footprint.
Class 70 to 100: standard freight, competitive rates. Automotive engines, sheet metal, hand tools, hardware, ceramic tile, bathroom fixtures, packaged appliances, tires, computers, and refrigerators. Most manufactured goods land somewhere in this range.
Class 110 to 175: moderate density, higher cost. Wood cabinets, framed artwork, small household appliances, auto body panels, bookcases, upholstered furniture, and boxed clothing. Items in this bracket take up more space relative to their weight.
Class 200 to 300: low density, premium rates. Flat-screen TVs in original manufacturer packaging, assembled outdoor furniture, mattresses, kayaks, and large assembled wood cabinets. Bulky packaging is usually the culprit. Repackaging to reduce void space can often move a shipment from Class 200 down to Class 150, which is a meaningful rate difference.
Class 400 to 500: very low density, most expensive. Inflatable products, foam cushions, ping pong balls, and other goods that occupy a full pallet footprint with almost no weight. If your freight falls here, consolidation or compression packaging almost always pays for itself in reduced freight cost.
This calculator uses density-based classification, which covers the majority of general freight. Certain commodities carry fixed NMFC item numbers that override density results entirely. Electronics, chemicals, and regulated materials are common examples. The assigned class for these goods is set in the NMFC directory and does not change based on how you package them.
Always confirm your final class with your carrier or freight broker before booking, especially for high-value shipments where a reclassification fee would be significant.
NMFC freight class is a standardized system (classes 50 to 500) used by LTL carriers to price shipments based on density, stowability, handling difficulty, and liability. If you declare the wrong class, carriers can reclassify your shipment at their terminal and charge a correction fee that can run hundreds of dollars above your original quote.
Density in pounds per cubic foot equals weight divided by cubic volume. Volume is length times width times height, divided by 1,728 to convert cubic inches to cubic feet. The resulting PCF value maps to a freight class. For example, freight denser than 50 PCF is Class 50, while freight below 1 PCF falls into Class 500.
Yes. LTL carriers measure and weigh freight as it sits on the pallet. Include the pallet footprint (typically 48 x 40 inches) in your length and width measurements and add pallet weight, usually 35 to 50 lbs for a standard wood pallet, to your gross weight for the most accurate class determination.
Certain commodities, including electronics, chemicals, and regulated materials, have fixed NMFC item numbers with prescribed classes that do not change with density. This calculator covers density-based classification, which applies to the majority of general freight. Consult the NMFC directory or your freight broker to check for commodity-specific class overrides.
NMFC classification is a North American standard used by LTL carriers in the United States and Canada. It does not apply to international ocean or air freight, which use separate weight-and-volume pricing models. For cross-border LTL moves within North America, NMFC classes still govern pricing on the domestic leg of the shipment.
Carriers inspect and measure shipments at pickup or at a terminal. Discrepancies arise when dimensions are measured to the outermost edge of shrink wrap or banding, when a commodity carries a fixed class override, or when a shipment is reclassified for stowability reasons. Using precise outer dimensions and including all packaging in your weight reduces reclassification risk significantly.