Freight Class Calculator

What Is a Freight Class?

Freight class is a standardized way to price LTL (Less Than Truckload) shipments. In the United States, freight class is defined by the NMFC (National Motor Freight Classification) system.

There are 18 freight classes, ranging from Class 50 (very dense and easy to ship) to Class 500 (light, bulky, and expensive to move).

Lower class = lower shipping cost
Higher class = higher shipping cost

Why Freight Class Matters

Freight class affects:

• Shipping rates
• Carrier acceptance
• Damage risk assessment
• Space planning inside a trailer

Even a small mistake in freight class can lead to reclassification fees, billing delays, or surprise charges after delivery.

That is why calculators like the one you shared are widely used.

What Is a Freight Class Calculator?

A Freight Class Calculator is a tool that estimates freight class using density, which is the most common NMFC method.

Density is calculated as:

Weight ÷ Volume

Your calculator automates this process. Instead of doing math by hand, you enter a few values and instantly get:

• Estimated freight class
• Total shipment volume
• Density in pounds per cubic foot (PCF)
• Approximate trailer capacity

Inputs Used in the Calculator

Let’s break down each input field from the calculator you provided.

1. Length, Width, and Height (inches)

These values define the size of one unit or pallet.

• Measure the longest points
• Include packaging and pallets
• Always round up, not down

Incorrect dimensions are one of the biggest causes of freight reclassification.

2. Quantity (Units)

This tells the calculator how many identical items are being shipped.

The calculator multiplies volume by quantity to get total shipment volume.

3. Total Weight (lbs)

This is the combined weight of all units, including:

• Products
• Pallets
• Crates
• Shrink wrap

Never enter per-unit weight unless you are shipping only one unit.

How the Freight Class Is Calculated

Here is what happens behind the scenes, explained simply.

Step 1: Convert Volume to Cubic Feet

The calculator converts inches to cubic feet using this formula:

Length × Width × Height ÷ 1728 × Quantity

This gives total volume in cubic feet.

Step 2: Calculate Density

Density is calculated as:

Total Weight ÷ Total Volume

The result is shown as lbs per cubic foot (PCF).

Step 3: Match Density to NMFC Class

The calculator compares density against a reference chart like this:

• Less than 1 PCF → Class 500
• 5 to 6 PCF → Class 175
• 10 to 12 PCF → Class 110
• Over 50 PCF → Class 60

The higher the density, the lower the freight class.

Understanding the Results Section

Once you click Calculate Class, the result panel shows several useful details.

Estimated Freight Class

Displayed clearly as:

Class 50 – Class 500

This is your primary pricing input for LTL carriers.

Density Bar (Visual Scale)

The color bar moves from:

• Red (light, bulky freight)
• Yellow (medium density)
• Green (dense freight)

This gives a quick visual sense of where your shipment falls.

Total Volume

Shows total space used in cubic feet.
This helps with trailer planning and load optimization.

Density (PCF)

Shows the exact density number used to determine class.
This is helpful when double-checking carrier invoices.

Estimated 53′ Trailer Capacity

This estimate shows how many identical units could fit in a standard 53-foot trailer, based on:

• Volume limits
• Weight limits

It is useful for planning full truckloads or consolidations.

Reference Chart Toggle

The Show/Hide Class Reference Chart option displays the full density-to-class table.

This is useful when:

• You want transparency
• You need to explain pricing to a client
• You are comparing multiple shipment options

Common Mistakes to Avoid

Even with a calculator, errors can happen. Watch out for these.

Using Incorrect Dimensions

Always measure the outermost points, not the product alone.

Forgetting Packaging Weight

Pallets and crates add weight quickly.

Guessing Instead of Measuring

Carriers verify shipments. Estimates often lead to reclass fees.

Mixing Units

This calculator expects inches and pounds only.

Who Should Use a Freight Class Calculator?

This tool is useful for:

• Small business owners
• Warehouse managers
• Freight brokers
• E-commerce sellers
• Anyone shipping LTL freight

If you ship more than once a month, a calculator like this saves time and money.