Freight Class Calculator
Find shipment density for LTL freight class.
Results update as you type.
How it works
Freight class determines what you pay to ship less-than-truckload freight, and density in pounds per cubic foot is the single most important factor behind it. This freight class calculator multiplies your shipment's length, width, and height, converts the result to cubic feet, and divides the weight by that volume to give the density carriers use as the starting point for assigning a class. This matters because the national freight classification system rates commodities from class 50 for dense, durable goods up to class 500 for light, bulky items, and higher classes cost more. For many products, density alone determines the class, so knowing your pounds per cubic foot lets you predict the class, quote accurately, and avoid the reclassification charges that hit when a carrier re-measures a shipment and finds it lighter or bulkier than declared. The calculation works because dividing cubic inches by 1,728 converts to the cubic feet that classification tables use, and dividing weight by volume yields the density those tables are built around. Denser freight packs trailers efficiently and earns a lower class, while low-density freight wastes space and climbs the scale. Note that some commodities are classed by factors beyond density, such as handling, stowability, and liability, so density gives the class for density-based items but not every one. Shippers, brokers, and warehouse teams calculate density before booking to estimate class, compare carrier quotes fairly, and package goods to reach a cheaper class where possible.
density = weight ÷ (length × width × height ÷ 1,728)
Freight class density divides the shipment weight by its volume in cubic feet, where volume comes from multiplying the three dimensions in inches and dividing by 1,728, the number of cubic inches in a cubic foot. The formula works because less-than-truckload carriers assign freight class largely on density, since it captures how efficiently a shipment uses trailer space. A higher density in pounds per cubic foot generally maps to a lower, cheaper class, making this figure the starting point for classifying and pricing LTL freight.
Source:Standard freight/logistics formula
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Worked example
How to use this calculator
- 1
Enter your values
Enter weight, length, width and height.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Density updates instantly as you type — no button to press.
Frequently asked questions
How does density map to a freight class?
Freight classes run from 50 to 500, and density-based tables assign lower classes to denser freight. Roughly, 30 or more pounds per cubic foot often lands around class 60 to 70, while under 1 pound per cubic foot can reach class 400 or higher. The exact mapping comes from the national classification tables, so use your calculated density to look up the corresponding class in the current schedule your carrier follows.
Is freight class always based on density?
Not always. For many commodities density is the primary driver, but the classification system also weighs handling, stowability, and liability. Fragile, hazardous, or hard-to-stack goods may carry a higher class than density alone suggests, and some items have a fixed class regardless of density. Use this calculator to get the density and the density-based class, then check the specific commodity listing, because those other factors can override a pure density result.
What happens if I declare the wrong class?
If a carrier inspects your shipment and finds the actual density or commodity differs from what you declared, they reclassify it and issue an adjusted, usually higher, charge plus possible fees. Reclassification is a common and avoidable cost. Measuring and weighing your shipment accurately, then calculating density with this tool before you book, helps you declare the correct class up front and avoid unexpected charges after pickup.
Should I measure the packaged shipment or the product?
Always measure the shipment exactly as it ships, including pallets, crating, and any overhang, and weigh the complete packaged load. Carriers rate the space the freight actually occupies, so packaging counts toward both volume and weight. Measuring the bare product understates volume and inflates density, which can produce the wrong class and trigger a reclassification when the carrier re-measures the real, packaged dimensions on the dock.
How do I lower my freight class?
Since density drives many classes, increasing density lowers the class and the cost. Use tighter packaging to reduce volume without adding much weight, consolidate loose items onto a single well-packed pallet, and remove excess void space. Stackable, sturdy packaging can also improve handling and stowability factors. Recalculate density after repackaging to confirm you have crossed into a lower class bracket before you book the shipment.