What Is Freight Class? A Complete Guide to Freight Class in U.S. LTL Shipping

If you ship freight through LTL (Less Than Truckload) services in the United States, you’ve probably heard the term: Freight Class

Freight Class

One of the most common issues shippers face when arranging LTL shipments is:

• Not knowing which Freight Class to use

• Getting reclassified by the carrier

• Receiving unexpected additional charges

• Paying much higher freight costs than originally quoted

In reality, Freight Class is one of the most important factors affecting LTL shipping rates in the U.S.

In this guide, we’ll explain:

• What Freight Class is

• How Freight Class affects shipping costs

• How Freight Class is calculated

• Common Freight Class examples

• How to avoid reclassification fees

What Is Freight Class?

Freight Class is a standardized classification system used in U.S. LTL trucking.

It is established by the National Motor Freight Traffic Association (NMFTA).

Freight Classes range from:

Class 50 to Class 500

Generally speaking:

• Lower class number → Lower shipping cost

• Higher class number → Higher shipping cost

Carriers determine Freight Class based on factors such as:

• Density

• Fragility

• Ease of handling

• Liability/value

• Stowability

Why Is Freight Class Important?

Because it directly affects:

1. Freight Rates

Two shipments with the same weight can have completely different rates depending on the Freight Class.

For example:

• Class 70

• Class 250

The shipping cost difference can easily be double or more.

2. Additional Charges

If the actual shipment does not match the declared information, the carrier may:

• Reclass the shipment

• Reweigh the shipment

This often results in additional charges.

This is one of the most common issues shippers encounter in LTL freight.

How Is Freight Class Calculated?

Freight Class is most commonly determined by:

Density

The formula is: Density=Weight(lbs) ÷ Length×Width×Height (In)​​x1728​

The unit is typically:

Pounds per Cubic Foot (PCF)

This measures how many pounds your freight weighs per cubic foot.

Why Does Density Matter?

Truck space is limited.

For example:

Scenario A

• 500 lbs

• One compact pallet

Scenario B

• 500 lbs

• Takes up half the trailer

Even though the weight is the same, Scenario B occupies much more space and therefore costs more to transport.

What Does a Higher Freight Class Mean?

A higher Freight Class generally means the freight is:

• More difficult to stack

• More fragile

• Higher risk

• More space-consuming

As a result, carriers charge higher rates.

What Is NMFC?

Many Freight Classes are associated with:

NMFC Codes

NMFC stands for:

National Motor Freight Classification.

Each commodity has its own NMFC code.

For example:

• Furniture

• Plastic products

• Electronics

• Metal parts

All may have different NMFC classifications.

Some freight classes are fixed, while others are density-based.

Common Mistakes Shippers Make

1. Incorrect Dimensions

Many shippers:

• Forget pallet height

• Underestimate packaging dimensions

• Use inaccurate measurements

This often leads to carrier reclassification.

2. Incorrect Weight

Estimated weights are often inaccurate, especially when provided by factories or suppliers.

3. Using the Wrong Freight Class

For example:

A shipment that should be:

• Class 175

is declared as:

• Class 70

This can trigger additional charges later.

How to Avoid Reclass Fees

Here are several important tips:

Use Accurate Dimensions

Always include:

• Pallet height

• Final packaged dimensions

• Outer carton measurements

Use Actual Weight

Do not estimate.

Whenever possible, weigh the shipment before pickup.

Ask Your Logistics Provider

A professional logistics company can help:

• Determine the correct Freight Class

• Identify the correct NMFC code

• Reduce reclass risk

Conclusion

Freight Class is one of the most important parts of U.S. LTL shipping.

It affects not only your freight cost, but also:

• Billing accuracy

• Additional charges

• Shipping efficiency

Providing accurate:

• Dimensions

• Weight

• Packaging information

• Freight classification

can help reduce shipping costs and avoid unnecessary disputes.

If you are unsure about the correct Freight Class for your shipment, it is always recommended to consult with an experienced logistics provider before shipping.