Freight Class Calculator
Density-based freight class from shipment dimensions and weight.
What it does
Freight class sorts less-than-truckload shipments into groups that carriers use for pricing. For density-based freight, the key number is pounds per cubic foot: a heavy, compact crate lands in a lower class than a light carton that takes the same floor space.
The tool above accepts dimensions and total weight in imperial or metric units. It returns freight density, the matching NMFTA density band, and shipment volume, so you can compare a quote against the cargo you actually have.
Density is not the only input in a real classification. The National Motor Freight Classification item can raise a class for difficult handling, poor stowability, or high liability. A drum of hazardous material and a stack of foam blocks can share a density but not a class.
Use the result as a planning number. Measure the shipment as it will be tendered, including pallets and packaging, then confirm the NMFC item and carrier rules before you rely on the class for a booking.
How to use
- Choose imperial or metric units. The form swaps the dimension and weight fields to match.
- Measure the shipment's outside length, width, and height in inches or centimeters.
- Enter the total weight in pounds or kilograms, including the pallet and packaging.
- Read the density first, then the class band beside it.
- Check the volume against the dimensions to catch a unit or decimal mistake.
- Confirm the NMFC item and carrier rules before using the class in a quote.
Formula
- length x width x height
- Outside volume of the shipment in cubic inches or cubic centimeters.
- 1,728
- Cubic inches in one cubic foot. Metric mode converts through cubic meters.
- weight
- Total shipment weight, including pallet, crate, and packaging.
- density band
- NMFTA threshold that assigns class 50 through 500.
A shipment at exactly 22.5 lb/ft3 falls in class 65 because the bands use the lower bound of each range. The metric path converts density to lb/ft3 before selecting the class, so both unit systems agree.
Worked example
Example: 48 x 40 x 36 in pallet, 1,000 lb
Imperial defaults: length 48 in, width 40 in, height 36 in, weight 1,000 lb.
- Volume in cubic inches: 48 x 40 x 36 = 69,120 in3.
- Convert to cubic feet: 69,120 / 1,728 = 40 ft3.
- Density: 1,000 lb / 40 ft3 = 25 lb/ft3.
- Read the band: 25 lb/ft3 sits between 22.5 and 30, so the class is 65.
- Tool shows 25 lb/ft3, Class 65, and 40 ft3.
- Metric check: 122 x 102 x 91 cm at 454 kg gives 400.9 kg/m3, which converts to the same 25 lb/ft3.
Reference table
| Density (lb/ft3) | Density (kg/m3) | Freight class |
|---|---|---|
| 50 or more | 801 or more | 50 |
| 35 to 49.9 | 561 to 800 | 55 |
| 30 to 34.9 | 481 to 560 | 60 |
| 22.5 to 29.9 | 360 to 480 | 65 |
| 15 to 22.4 | 240 to 359 | 70 |
| 13.5 to 14.9 | 216 to 239 | 77.5 |
| 12 to 13.4 | 192 to 215 | 85 |
| 10.5 to 11.9 | 168 to 191 | 92.5 |
| 9 to 10.4 | 144 to 167 | 100 |
| 8 to 8.9 | 128 to 143 | 110 |
| 7 to 7.9 | 112 to 127 | 125 |
| 6 to 6.9 | 96 to 111 | 150 |
| 5 to 5.9 | 80 to 95 | 175 |
| 4 to 4.9 | 64 to 79 | 200 |
| 3 to 3.9 | 48 to 63 | 250 |
| 2 to 2.9 | 32 to 47 | 300 |
| 1 to 1.9 | 16 to 31 | 400 |
| Below 1 | Below 16 | 500 |
Limits
- Density is only one classification factor. The applicable NMFC item can require a different class for handling, stowability, or liability.
- Assumes a rectangular shipment with no unusual protrusions. Irregular shapes need a practical volume or carrier measurement.
- Uses the dimensions and weight you enter. Pallet overhang, packaging, and accessorials can change the billed class.
- Does not quote freight rates, discounts, minimum charges, or fuel surcharges.
Common mistakes
- Dividing pounds by cubic inches and treating the result as pounds per cubic foot.
- Using inside carton dimensions instead of the outside shipment dimensions.
- Leaving the pallet weight out of the total.
- Assuming a density class overrides the NMFC item for fragile or hazardous goods.
- Mixing inches with centimeters in the same shipment entry.
Try it yourself
Quick checks. Answers sit tucked under each question.
A carton measures 40 x 30 x 30 in and weighs 600 lb. What density and class does the tool return?
Volume is 40 x 30 x 30 / 1,728 = 20.83 ft3. Density is 600 / 20.83 = 28.8 lb/ft3, which falls in class 65.
A crate measures 24 x 18 x 12 in and weighs 100 lb. What is its class?
Volume is 24 x 18 x 12 / 1,728 = 3 ft3. Density is 100 / 3 = 33.33 lb/ft3, so the class is 60.
A metric shipment is 120 x 80 x 100 cm and 300 kg. What density and class does it get?
Volume is 0.96 m3 and density is 312.5 kg/m3, or about 19.5 lb/ft3. That is class 70.
Questions
Is freight class the same as NMFC class?
Freight class is the class number assigned through the National Motor Freight Classification. The NMFC item for your commodity sets the rules, and density is one input.
What density is class 100?
Class 100 covers shipments from 9 to 10.4 lb/ft3 in the density table used here. The exact NMFC item can still change the result.
Do I include the pallet in the weight and dimensions?
Yes. Carriers rate the shipment as tendered, so include the pallet, crate, strapping, and any packaging that adds size or weight.
Why did my carrier quote a different class?
The carrier may apply a different NMFC item, measure the freight differently, or add a handling or liability adjustment. A density estimate is not a classification ruling.
Can I use this for parcel shipping?
Parcel services usually price by dimensional weight and service level, not LTL freight class. Use a dimensional weight calculator for parcel quotes.
Does a higher class cost more?
Usually yes. Higher classes generally carry higher rates, but the linehaul rate, discounts, minimum charge, and accessorials also affect the final price.