Freight Class Calculator

Estimate NMFC freight class from your shipment's density and dimensions.

Shipment Information

Total Shipment Weight

Package Dimensions

Dimension Units

Package 1

Length

Width

Height

Quantity

Freight Class Reference Table

The 18 NMFC freight classes and the density ranges most commonly associated with them. Denser freight earns a lower class and a lower rate.

Class	Density (lb/ft³)	Typical Products	Characteristics
50	50+	Bricks, sand, nuts & bolts, steel plate, dense flooring	Extremely dense and durable, stows and stacks easily, very low liability.
55	35 – 50	Cement, hardwood flooring, moldings, construction materials	Very dense, palletised, durable — among the cheapest freight to move.
60	30 – 35	Car parts, steel cabling, dense machined goods	Dense and sturdy, ships and stores efficiently, low handling risk.
65	22.5 – 30	Car accessories, bottled beverages, books, boxed goods	Solid density, easy to palletise and stack, minimal fragility.
70	15 – 22.5	Auto engines, food items, cast machined parts	Good density with straightforward handling and storage.
77.5	13.5 – 15	Tires, bathroom fixtures, boxed hardware	Moderately dense, standard handling, average liability.
85	12 – 13.5	Crated machinery, cast-iron stoves, transmissions	Average density; handling and stowability are typical.
92.5	10.5 – 12	Computers, monitors, refrigerators, appliances	Mid-range density; often fragile, so liability rises.
100	9 – 10.5	Boat & car covers, canvas, wine cases, crated goods	Below-average density; bulk starts to outweigh weight.
110	8 – 9	Cabinets, framed artwork, table saws	Bulky for its weight; handling care and space both increase.
125	7 – 8	Small household appliances, boxed light goods	Light and bulky; takes more trailer space per pound.
150	6 – 7	Auto sheet metal, bookcases, assembled furniture	Low density; awkward to stow and higher liability.
175	5 – 6	Clothing, couches, stuffed furniture	Very light for its size; consumes lots of space.
200	4 – 5	Aircraft parts, aluminum tables, packaged mattresses	Bulky and light; handling and stowability are challenging.
250	3 – 4	Mattresses & box springs, plasma TVs, bamboo furniture	Fragile and voluminous; high handling and liability.
300	2 – 3	Wood cabinets, tables, chairs, model boats	Mostly air by volume; expensive to move per pound.
400	1 – 2	Deer antlers, very light bulky goods	Extremely low density; among the priciest to ship.
500	< 1	Ping-pong balls, bags of gold dust, low-density high-value goods	Highest class — least dense and/or highest liability.

Density ranges follow widely used NMFC density guidelines. The official class for a specific commodity is set by its NMFC item number and may differ.

What Is Freight Class?

Freight class is a standardized code from the National Motor Freight Classification (NMFC) that carriers use to price less-than-truckload (LTL) shipments consistently. Every commodity falls into one of 18 classes, numbered 50 to 500. A low class means dense, durable, easy-to-handle freight that costs less to ship; a high class means light, bulky, fragile, or high-value freight that costs more. Getting the class right is the difference between an accurate quote and a surprise re-class charge on your invoice.

This calculator estimates your class from the one factor you can measure yourself — density — and pairs it with a cost analyzer, packaging optimizer, and what-if tool. To plan the whole shipment, combine it with our Unit Converter for weight and length conversions, the Cubic Yard Calculator for volume, and the Board Foot Calculator for lumber loads.

How Freight Class Is Determined

Measure the shipment

Record the length, width, and height of every handling unit plus the total weight. Round dimensions up to the nearest inch the way carriers do at the dock, packaging included.

Calculate the volume

Multiply length × width × height for each piece and divide by 1,728 to convert cubic inches to cubic feet, then add every piece together for the total cube.

Find the density

Divide total weight (lb) by total volume (ft³). Density in pounds per cubic foot is the number that drives most freight class assignments.

Map to a freight class

Match the density to the standard NMFC density scale — higher density means a lower, cheaper class. Then confirm handling, stowability, liability, and the NMFC item number.

Understanding NMFC

The NMFC is published by the National Motor Freight Traffic Association (NMFTA). It assigns every commodity an item number and a class based on four transportation characteristics. Density is usually the headline factor, but the other three matter and can override it:

Density — weight per cubic foot; how efficiently the freight uses trailer space.
Handling — how easy the freight is to load, unload, and move, including weight, fragility, and shape.
Stowability — how well it fits alongside other freight; hazardous, oversized, or oddly shaped goods stow poorly.
Liability — risk of damage, theft, or spoilage, and the value of the goods.

3 Ways to Use This Calculator

Quote LTL shipments faster

Estimate the class before you request rates so carrier quotes come back accurate the first time, with fewer re-class adjustments landing on your invoice later.

Right-size your packaging

Use the optimizer to see how much cube you'd need to remove to reach the next lower class, then choose a smaller carton or tighter pallet build to capture the savings.

Compare shipping scenarios

Run the what-if analysis to test heavier loads, extra pallets, or consolidated packaging and watch the freight class and relative cost update instantly.

Freight Density Explained

Density is simply weight divided by volume. To find it, measure the length, width, and height of each handling unit (packaging and pallet included), multiply them to get cubic inches, and divide by 1,728 to convert to cubic feet. Add every piece together for the total cube, then divide your total weight in pounds by that total cube. The result — pounds per cubic foot — is what maps to a freight class.

Why does it dominate pricing? Trailers “run out” of either weight capacity or space. Dense freight fills the weight allowance without hogging space, so carriers can sell the rest of the trailer to other customers — and reward you with a lower class. Light, bulky freight takes up sellable space for little weight, so it lands in a higher class.

Density vs Commodity Classification

Density-based classes

Many commodities are classed on a sliding density scale: the denser the shipment, the lower the class. For these goods, this calculator's estimate is usually very close to the assigned class, and improving density directly lowers your cost.

Fixed-item classes

Other commodities carry a fixed class set by their NMFC item number, no matter how dense the shipment is. Electronics, hazmat, and certain automotive parts are common examples. Always confirm whether your item is density-based or fixed.

Factors That Affect Freight Class

Beyond density, the class you're charged is shaped by how the freight behaves in the network. Packaging that's sturdy and stackable improves stowability. Fragile or high-value goods raise liability. Oversized or protruding items are harder to handle and stow. And accessorial needs — a residential address, a liftgate, or a limited-access delivery — don't change the class itself but do add to the final invoice.

Because so many factors interact, two shipments with identical density can be classed differently. That's why this tool flags handling, stowability, and liability, and why you should always confirm the NMFC item number with your carrier.

Packaging Best Practices & How to Reduce Freight Costs

Raise your density

Right-size cartons to the product, cut void fill, consolidate loose pieces onto one pallet, and square up loads so nothing overhangs. Every cubic foot of air you remove at the same weight pushes density up and class down.

Protect and stack

Use rigid, stackable packaging so carriers can load freight on top — non-stackable shipments effectively rent the space above them. Sturdy packaging also lowers liability and the chance of a damage claim.

Declare accurately

Weigh and measure the finished handling unit and declare the correct NMFC item. Accurate paperwork avoids re-class fees, which are among the most common — and avoidable — LTL surcharges.

Compare and consolidate

Batch small shipments into fewer, denser handling units, and compare carriers — class, base rates, and discounts vary. For heavy dense loads, also compare LTL against volume/partial-truckload options.

How Freight Class Impacts Shipping Costs

LTL carriers publish base rates per hundredweight (per 100 lb) for each class between an origin and destination. A higher class carries a higher base rate, so the same 500-pound shipment can cost noticeably more at Class 250 than at Class 70. On top of the class-driven base rate, your final price reflects distance, fuel surcharges, and accessorials.

Because class multiplies through the whole rate, lowering it — usually by raising density — is one of the highest-leverage things a shipper can do. That's exactly what the cost analyzer and packaging optimizer above are built to help you find.

When Density Alone Is Not Enough

A density estimate is an excellent starting point, but it is not a final answer. Fixed-item commodities, hazardous materials, high-value goods, and unusually shaped or fragile freight can all be classed independently of density. When handling, stowability, or liability dominate, the official class can sit well above what density alone would suggest. Treat this calculator as a planning tool and verify the NMFC item number with your carrier or an NMFTA source before you book.

The Core Freight Formulas

Volume (ft³)

(L × W × H in inches) ÷ 1,728

Density

Total weight (lb) ÷ total volume (ft³)

Metric density

lb/ft³ × 16.018 = kg/m³

Multiply each package's dimensions, convert to cubic feet, and sum across all pieces for total volume. Divide total weight by total volume to get the density that maps to a freight class.

Common Freight Classification Mistakes

1
Measuring the product, not the package. Density is based on the full shipping footprint — pallet, packaging, and overhang all count. Always measure the outside of the finished handling unit.
2
Forgetting to round up. Carriers round each dimension up to the next inch and weight up to the next pound. Rounding down understates your cube and invites a re-class fee.
3
Assuming density is the only factor. Some commodities carry a fixed NMFC item number, and handling, stowability, and liability can override density entirely.
4
Ignoring pallet weight and height. The pallet itself adds weight and cube. Leaving it out of the calculation skews density and the resulting class.
5
Not re-checking after packaging changes. A new box size, added void fill, or a different pallet pattern changes density — and can change your class and rate.

Freight class ranges on this page follow standard NMFC density guidelines published by the National Motor Freight Traffic Association (NMFTA). Results are educational planning estimates, not an official classification — the assigned class depends on the NMFC item number and each carrier's rules. Last reviewed 2026-07-06. See our methodology and editorial standards.

Frequently Asked Questions

Freight class is a standardized code from the National Motor Freight Classification (NMFC) that groups commodities into 18 classes from 50 to 500. Carriers use it to price less-than-truckload (LTL) shipments consistently. A lower class (like 50) means dense, easy-to-handle freight that costs less to ship, while a higher class (like 500) means light, bulky, fragile, or high-liability freight that costs more.

The most common starting point is density — your shipment's weight in pounds divided by its volume in cubic feet. Measure length, width, and height, multiply them to get cubic inches, divide by 1,728 to get cubic feet, then divide total weight by that volume. This calculator does all of that and maps the result to a class using standard NMFC density guidelines. The official class, however, also weighs handling, stowability, and liability.

NMFC stands for the National Motor Freight Classification, a system published by the National Motor Freight Traffic Association (NMFTA). It assigns every commodity an item number and a class based on four transportation characteristics: density, handling (ease of loading), stowability (how it fits with other freight), and liability (risk of damage, theft, or spoilage). Carriers reference the NMFC to rate shipments fairly.

Density is the single biggest driver of freight class for most commodities. Trailers fill up either by weight or by space, so a dense shipment that packs a lot of weight into a small footprint uses capacity efficiently and earns a lower, cheaper class. A light, bulky shipment takes up space carriers can't sell to anyone else, so it lands in a higher class. Improving density is usually the fastest way to reduce LTL cost.

Class 50 is the lowest and least expensive freight class. It applies to extremely dense, durable, easy-to-stow goods — think sand, bricks, nuts and bolts, or steel plate — typically with a density of 50 pounds per cubic foot or more. Because these shipments use trailer space so efficiently and carry low damage risk, they receive the most favorable rates.

Class 500 is the highest and most expensive freight class. It covers very low-density items (under 1 pound per cubic foot) or goods with high liability and handling requirements — for example ping-pong balls or bags of gold dust. These shipments either consume a lot of space for very little weight or carry significant value and risk, so they command premium rates.

Yes. Packaging changes both the volume and the handling profile of a shipment. Oversized boxes filled with void fill lower your density and can bump you into a higher, costlier class, while right-sizing cartons and palletising loose pieces raises density and can lower the class. Sturdy, stackable packaging also improves stowability, which factors into the official NMFC assessment.

Yes. Carriers regularly re-weigh and re-measure freight at their docks. If the actual density, dimensions, or commodity differ from what you declared, they can re-classify the shipment and issue a corrected charge, often with an inspection fee. Declaring accurate weight, dimensions, and the correct NMFC item up front is the best way to avoid these adjustments.

No. Density is the primary factor for most commodities and the one you can calculate yourself, but the NMFC also considers handling, stowability, and liability. Some commodities are assigned a fixed class by their NMFC item number regardless of density, and hazardous materials follow separate rules. That's why this tool is a planning estimate, not a substitute for an official classification.

This calculator accurately computes your shipment's volume and density and maps that density to a freight class using widely used NMFC density guidelines, so it's a reliable planning estimate for density-driven freight. It cannot see the official NMFC item number assigned to your specific commodity or account for special handling, stowability, and liability rules, so always confirm the final class with your carrier or an NMFTA source before booking.