How is freight class calculated?

Freight class is primarily determined by density: Density (lbs/ft³) = Total Weight ÷ Total Cubic Feet. Higher density = lower class number = cheaper shipping rate.

Freight Class Calculator — NMFC Density Calculator for US LTL Shipping

Q: What is freight class?

Freight class is a standardized classification system (NMFC) used by US LTL carriers to categorize freight based on density, stowability, handling, and liability. Classes range from 50 (densest) to 500 (lightest).

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Freight Class (NMFC Density) Calculator

Measurement System

Quantity

Length (in)

Width (in)

Height (in)

Weight (lbs)

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Full NMFC Freight Class Chart

Freight Class	Density (lbs/ft³)	Typical Commodities
50	≥50	Fits on pallet. Dense metals, bricks, hardwood floors
55	35–50	Dense cargo, car accessories
60	30–35	Car accessories, machinery parts
65	22.5–30	Bottled beverages, auto parts
70	15–22.5	Food items, auto parts
77.5	13.5–15	Tires, bathroom fixtures
85	12–13.5	Crated machinery, castings
92.5	10–12	Computers, monitors, refrigerators
100	9–10	Boat covers, car covers
110	8–9	Cabinets, framed artwork
125	7–8	Small appliances
150	6–7	Auto sheet metal parts
175	5–6	Clothing, couches, stuffed furniture
200	4–5	Sheet metal parts, aluminum tables
250	3–4	Bamboo furniture, mattresses
300	2–3	Wood cabinets, tables, chairs
400	1–2	Ping pong balls, deer antlers
500	<1	Gold dust, bags of air, low-density items

What is Freight Class?

Freight class is a standardized classification system developed by the National Motor Freight Traffic Association (NMFTA) and used by virtually all US LTL (Less than Truckload) carriers. It categorises shipments into 18 classes ranging from 50 to 500, and directly determines your shipping rate.

LTL carriers use freight class because different types of cargo have different handling requirements, space consumption, and risk profiles. A pallet of steel parts (class 50) is very different from a shipment of ping-pong balls (class 400) — even if they weigh the same.

The Four NMFC Classification Factors

While density is the most common determining factor, NMFC classification technically considers four characteristics:

Factor	Description	Impact
Density	Weight relative to space occupied (lbs/ft³)	Primary factor — higher density = lower class
Stowability	How easily cargo stacks and fits with other freight	Odd shapes or hazmat = higher class
Handling	Ease and risk of loading/unloading	Fragile or awkward items = higher class
Liability	Risk of theft, damage, or spoilage	High-value or perishable = higher class

How to Calculate Freight Class by Density

Step 1: Volume (ft³) = (L × W × H in inches) ÷ 1,728

Step 2: Density (lbs/ft³) = Total Weight (lbs) ÷ Volume (ft³)

Step 3: Match density to the NMFC class chart above

Example: A pallet measuring 48" × 40" × 48" weighing 500 lbs:
Volume = (48 × 40 × 48) ÷ 1,728 = 53.3 ft³
Density = 500 ÷ 53.3 = 9.38 lbs/ft³ → Freight Class 92.5

Frequently Asked Questions

LTL carriers price by class because higher-class (lighter, bulkier) freight occupies more truck space per dollar of value, is harder to handle, and poses higher risk. Class 500 can cost 10× more per pound than Class 50.

Carriers inspect and re-weigh shipments. If your declared class is too low, you'll receive a reclassification charge — often significantly higher than if you'd declared correctly. Always measure accurately.

No — freight class (NMFC) is a US domestic LTL system. International ocean freight uses CBM and W/M tons. Air freight uses volumetric weight (÷6000). Use our Chargeable Weight Calculator for international shipments.