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LTL Freight Classification 101: Everything You Need to Know
If you’ve ever requested an LTL freight quote only to receive a higher amount on the final invoice, freight class may be the reason.
Freight classification is one of the biggest factors affecting LTL shipping costs, yet it’s also one of the least understood. An incorrect freight class can lead to reclassification charges, invoice adjustments, and unexpected shipping costs. Even experienced shipping teams occasionally encounter problems when products, packaging, or industry standards change.
The good news is that freight class isn’t nearly as complicated as it sounds. Once you understand how carriers classify freight and what they evaluate, you’ll be better equipped to request accurate quotes, avoid unnecessary surprises, and make more informed shipping decisions.
In this guide, you’ll learn what freight class is, how the National Motor Freight Classification (NMFC) system works, how freight class affects shipping costs, and how to reduce the risk of freight reclassification.
What is freight class?
Freight class is a standardized system used to classify shipments moving through the less-than-truckload (LTL) network. Developed by the National Motor Freight Traffic Association (NMFTA), the NMFC system assigns eligible commodities one of 18 freight classes, ranging from Class 50 to Class 500.
Rather than relying on weight alone, freight class evaluates a shipment’s transportation characteristics. It gives carriers a consistent way to compare thousands of products moving through the same network, helping them price freight fairly, maximize trailer space, and improve efficiency.
In general, dense, durable products receive lower freight classes because they make more efficient use of trailer space and are typically easier to handle. Lightweight, bulky, or fragile shipments generally receive higher freight classes because they occupy more trailer space, require specialized handling, or present greater transportation risk.
How NMFC codes and freight class work together
Although the terms NMFC code and freight class are often used interchangeably, they aren’t the same thing. They work together, but each serves a different purpose in the freight classification process.
An NMFC item number (commonly called an NMFC code) identifies the commodity being shipped. Every commodity listed in the National Motor Freight Classification (NMFC) system has its own item number. Depending on the commodity, that item number is either assigned a specific freight class or provides the criteria used to determine the correct freight class.
A freight class, on the other hand, describes the shipment’s transportation characteristics. It reflects how the shipment moves through the LTL network and is one of the factors carriers use when calculating shipping rates.
NMFC item number vs. freight class
Think of it this way: There are thousands of NMFC item numbers, each representing a specific commodity. Those thousands of commodities ultimately flow into 18 freight classes, which group products with similar transportation characteristics. In other words, NMFC item numbers are like individual raindrops, while the 18 freight classes are the buckets that collect them.
That’s why the rest of this guide focuses primarily on freight class. Once the correct NMFC item number is identified, freight class becomes the standard language carriers use to classify and price LTL shipments.
LTL freight class chart: Understanding all 18 classes
The National Motor Freight Classification (NMFC) system includes 18 freight classes, ranging from Class 50 to Class 500. These classifications help carriers evaluate how freight uses trailer space, how easily it can be handled, and the transportation risks it presents.
The following LTL freight class chart provides a reference for all 18 classes. In general, lower classes are associated with dense, durable freight, while higher classes often reflect shipments that occupy more space or present additional handling challenges.
Does every commodity follow the same LTL freight class chart?
No. Although the NMFC system uses 18 classes, not every commodity follows the same density thresholds. Some commodities have fixed classes, while others follow density-based scales or have additional classification requirements.
For example, a shipment with a density of 11.25 pounds per cubic foot (PCF) would fall within Class 92.5 under the standard 13-subprovision density scale. However, that class applies only if the commodity’s NMFC item uses this scale and its other classification requirements are satisfied.
Important: This chart is a general reference, not a universal classification calculator. Always verify the correct NMFC item number before assigning an LTL freight class.
How to determine LTL freight class step by step
Determining the correct LTL freight class starts with identifying what you’re shipping. Weight and dimensions matter, but you’ll also need to confirm the commodity and the NMFC rules that apply to it.
The following five steps explain how to determine freight class and reduce the risk of classification errors before requesting an LTL quote.
Step 1: Identify the commodity
Start with an accurate description of the product, including its material, construction, intended use, and packaging. This information helps identify the appropriate NMFC item number.
Some commodities have a fixed class, while others use density-based criteria or additional classification requirements.
Step 2: Measure the packaged shipment
Measure the shipment’s length, width, and height in inches. Include the pallet, packaging, and any materials that extend beyond the pallet’s edges.
For example, a shipment on a standard pallet might measure 48 inches long, 40 inches wide, and 60 inches high.
Step 3: Determine the total shipment weight
Weigh the shipment after it’s fully packaged and secured. Include the pallet and all protective materials.
For this example, assume the complete shipment weighs 750 pounds.
Step 4: Calculate freight density
Freight density measures how much a shipment weighs relative to the space it occupies. It’s expressed in pounds per cubic foot.
First, calculate the shipment’s volume:
48 × 40 × 60 ÷ 1,728 = 66.67 cubic feet
Next, divide the shipment’s weight by its volume:
750 ÷ 66.67 = 11.25 PCF
The shipment has a freight density of approximately 11.25 pounds per cubic foot.
Step 5: Verify the NMFC item and freight class
Under the standard NMFC 13-subprovision density scale, a density of 11.25 PCF falls within the Class 92.5 range.
However, that doesn’t automatically mean the shipment is Class 92.5. The applicable NMFC item must use that scale, and any other classification requirements must be satisfied.
Confirm the classification with your carrier or transportation provider before booking.
LTL classification examples: How density affects freight class
Consider three hypothetical shipments with identical dimensions but different weights.
| Shipment | Dimensions | Weight | Density | Illustrative class* |
| A | 48 × 40 × 60 in. | 400 lbs. | 6 PCF | 125 |
| B | 48 × 40 × 60 in. | 750 lbs. | 11.25 PCF | 92.5 |
| C | 48 × 40 × 60 in. | 1,200 lbs. | 18 PCF | 70 |
Classes assume the applicable NMFC item uses the standard 13-subprovision density scale. Actual classifications depend on the commodity and its NMFC requirements.
All three shipments occupy the same amount of trailer space, but their different weights produce different densities. Under the specified density scale, denser shipments receive lower freight classes.
This is why accurate measurements matter in LTL classification. Changes in packaged weight or dimensions can affect the assigned class when a commodity uses density-based criteria.
LTL freight class calculator: Estimate your shipment’s density
Calculating freight density manually can take time, especially when you’re preparing multiple LTL shipments. A freight class calculator simplifies the process by using shipment weight and dimensions to calculate density and, where applicable, estimate a potential class.
To get started, gather your shipment’s total packaged weight, length, width, and height. Include the pallet and all packaging materials so the measurements accurately reflect the freight being transported.
Use the ShipStation density calculator below to enter your shipment’s measurements and calculate its density in seconds. You can use the results to help evaluate your LTL freight class before requesting a shipping quote.
Density
Can a freight class calculator determine your exact class?
Not always. A calculator can determine freight density and may estimate a class using a particular density scale. However, LTL classification also depends on the applicable NMFC item and any special requirements involving handling, stowability, or liability.
For the most reliable result, use the calculator alongside the correct NMFC item number and confirm the classification before booking.
For a deeper explanation, see our freight density calculator guide.
Why freight class matters
Many businesses assume freight class only affects shipping rates. In reality, it influences nearly every stage of the LTL shipping process, from the accuracy of your initial quote to how your shipment is loaded, transported, and ultimately billed.
Unlike full truckload shipping, where a single shipment often fills an entire trailer, LTL carriers combine freight from multiple businesses into one load. Every pallet shares limited trailer space, but not every shipment has the same transportation requirements. Freight class gives carriers a standardized way to evaluate those differences.
One trailer. Three very different shipments.
Imagine a trailer carrying the following freight.
At first glance, two shipments that weigh the same might seem like they should cost the same to transport. But 500 pounds of empty plastic containers can occupy far more trailer space than 500 pounds of steel fasteners. The steel fasteners pack the same weight into a much smaller footprint, making more efficient use of the trailer. That’s why freight class considers density, not weight alone.
The four factors that determine freight class
Every shipment is different, but carriers generally evaluate the same four transportation characteristics when assigning a freight class. Rather than relying on a single measurement, they consider all four factors together to determine how efficiently and safely a shipment moves through the LTL network.
Density
Shipments that pack more weight into a smaller footprint generally receive lower freight classes because they make more efficient use of available trailer space. Lower-density shipments carrying the same weight occupy more space, which can result in a higher freight class.
Handling
Handling refers to how easily a shipment can be loaded, unloaded, and moved through the LTL network. Oversized, fragile, oddly shaped, or hazardous freight often requires additional labor, specialized equipment, or extra care during transit, which can increase its freight class.
Stowability
Stowability describes how easily a shipment fits alongside other freight in an LTL trailer. Standard palletized freight is generally easier to load than oversized or irregularly shaped shipments, which can limit how efficiently trailer space is used and contribute to a higher freight class.
Liability
Liability reflects the transportation risk associated with a shipment. Fragile, high-value, temperature-sensitive, or hazardous freight is generally more susceptible to damage, theft, or claims, making liability another factor carriers consider when assigning a freight class.
Key takeaway: Freight class isn’t based on a single measurement. Carriers evaluate density, handling, stowability, and liability together to determine how a shipment fits into the LTL network.
How freight class affects LTL shipping costs
LTL classification is one of the primary factors carriers use to calculate LTL shipping rates, but it isn’t the only one. Your final shipping cost depends on several variables, including shipment weight, dimensions, distance, and any additional services required for pickup or delivery.
In general, shipments assigned lower freight classes cost less to transport because they’re denser, easier to handle, and make better use of trailer space. Higher freight classes typically cost more because they occupy more space, require specialized handling, or present greater transportation risk.
Freight class is one piece of the pricing puzzle
When preparing an LTL quote, carriers typically consider the following factors.
No single factor determines your shipping rate. Carriers evaluate all this information together to generate an accurate quote.
What is freight reclassification?
Freight reclassification occurs when a carrier determines that the freight class listed on the bill of lading doesn’t accurately match the shipment being transported. If the shipment’s weight, dimensions, packaging, or commodity description differs from the information used to generate the original quote, the carrier may assign a different freight class and adjust the shipping charges accordingly.
Although receiving a higher invoice can be frustrating, reclassification usually isn’t a penalty. It’s simply the carrier correcting the shipment to reflect the appropriate freight class.
Common reasons freight gets reclassified
The more accurate your shipment information is before pickup, the less likely you are to receive billing adjustments after delivery.
How to avoid freight reclassification
While reclassification can’t always be prevented, it can often be avoided by verifying your shipment information before requesting a quote.
Before shipping, make sure you:
✔ Weigh the shipment after it’s fully packaged.
✔ Measure the pallet’s length, width, and height.
✔ Use an accurate commodity description.
✔ Confirm the correct NMFC item number or freight class, if applicable.
✔ Make sure the bill of lading accurately reflects the shipment being picked up.
Spending a few extra minutes verifying these details can improve quote accuracy, reduce billing disputes, and help keep your shipment moving without unnecessary delays.
What to do if your LTL freight class gets changed
Even when you’ve carefully prepared a shipment, a carrier may determine that its LTL freight class needs to change. This typically happens when an inspection identifies differences between the shipment’s actual characteristics and the information provided during quoting.
A reclassification can result in a higher freight bill, although some adjustments may reduce charges. The difference depends on the corrected class, carrier pricing, and applicable contract terms.
If you receive a reclassification adjustment, don’t automatically assume the new charges are correct. Review the supporting information to determine whether the change is justified.
Five steps to review or dispute a freight reclassification
1. Review the original shipping documents. Compare the original quote, bill of lading (BOL), commodity description, NMFC item number, and declared freight class with the revised invoice.
2. Request the carrier’s inspection findings. Ask for the measurements, weight records, inspection notes, or other documentation supporting the adjustment. These records can help explain why the carrier changed the classification.
3. Verify the applicable NMFC requirements. Confirm that the carrier used the correct commodity item number and classification criteria. If density determines the class, recalculate it using the documented measurements.
4. Gather supporting evidence. Photographs of the packaged shipment, warehouse scale records, packing specifications, and original shipping documents may help establish the shipment’s characteristics.
5. Submit a dispute when appropriate. If the adjustment appears incorrect, contact your carrier or transportation provider. Submit the relevant documentation and request a review. Follow the carrier’s dispute procedures and applicable deadlines.
What if the carrier’s reclassification is correct?
If the carrier’s findings are accurate, use the adjustment to improve future shipments. Update your product records, packaging measurements, or NMFC information so subsequent quotes reflect the correct classification.
Tracking LTL classification adjustments can also reveal recurring problems. For example, repeated changes involving the same product may indicate outdated dimensions, inconsistent packaging, or an incorrect commodity description.
The goal isn’t simply to challenge an unexpected invoice. It’s to understand why the adjustment occurred and prevent the same problem from affecting future shipments.
Glossary of LTL freight class and classification terms
Understanding LTL classification is easier when you’re familiar with the terminology carriers use. This glossary explains 20 common freight classification terms you’ll encounter when preparing shipments, requesting quotes, and reviewing invoices.
Frequently asked questions about LTL freight class
What is the most common LTL freight class?
There’s no single freight class that applies to most shipments. LTL classification depends on the commodity, its packaging, density, and applicable NMFC requirements. Businesses shipping different products may regularly use several freight classes.
What is Class 50 freight?
Class 50 is the lowest of the 18 freight classes. Under the standard 13-subprovision density scale, it applies to eligible commodities with densities of at least 50 PCF. Other commodities may qualify under different NMFC provisions.
What is Class 70 freight?
Under the standard 13-subprovision density scale, Class 70 applies to eligible commodities with densities of at least 15 but less than 22.5 PCF. The applicable NMFC item determines whether that scale applies.
What is Class 92.5 freight?
Class 92.5 corresponds to densities of at least 10 but less than 12 PCF under the standard 13-subprovision scale. However, commodities with different NMFC classification requirements may receive Class 92.5 for other reasons.
What is Class 125 freight?
Class 125 applies to eligible commodities with densities of at least 6 but less than 8 PCF under the standard 13-subprovision density scale. The actual classification depends on the applicable NMFC item.
What is Class 500 freight?
Class 500 is the highest freight class. It may apply to commodities with particularly challenging transportation characteristics, including extremely low density or special handling considerations, depending on their NMFC classification requirements.
Can two products with the same density have different freight classes?
Yes. Two products can have identical densities but different classifications because their NMFC items may have different requirements. Handling, stowability, and liability can influence classification independently of density.
Does pallet weight count when calculating freight density?
Yes. Include the pallet, packaging, and protective materials when determining the shipment’s total weight. You must also measure the shipment’s complete packaged dimensions to calculate density accurately.
Can packaging change a shipment’s LTL freight class?
Yes. Different packaging can change a shipment’s dimensions, density, or handling characteristics. For commodities subject to density-based classification, these changes may affect the assigned freight class.
Does stacking freight change its classification?
Potentially. Stackable packaging can affect how efficiently freight uses trailer space, while nonstackable configurations may create additional space requirements. Whether this changes classification depends on the applicable NMFC rules and shipment characteristics.
How do you classify a shipment containing multiple commodities?
Each commodity may require its own NMFC item number and freight class. Depending on the applicable rules and carrier requirements, the shipment may need separate line items identifying each commodity’s weight and classification.
Can freight class change between shipments of the same product?
Yes. A product may receive different classes when its packaging, density, or other relevant characteristics change. This is especially important for commodities classified under density-based NMFC provisions.
Do all LTL carriers use the same freight classification system?
The NMFC provides a widely used industry standard, but carriers may establish their own tariffs, pricing rules, or classification exceptions. Review the applicable carrier agreement when confirming how a shipment will be rated.
Is freight class required on a bill of lading?
Freight class and NMFC information are commonly requested for class-rated LTL shipments. Exact documentation requirements depend on the carrier and service agreement. Accurate commodity descriptions and shipment details remain essential.
Can you ship LTL freight without knowing its class?
Often, yes. A freight broker, carrier, or transportation provider may help determine the appropriate classification. You’ll still need accurate information about the commodity, packaging, weight, and dimensions.
What’s the difference between a freight reweigh and reclassification?
A reweigh corrects the shipment’s declared weight, while reclassification changes its assigned freight class. A reweigh can also trigger reclassification when the corrected weight changes a shipment’s density-based classification.
Can a carrier change freight class after delivery?
Yes. A carrier may identify classification discrepancies during shipment processing or subsequent billing reviews. Adjustments can occur after delivery, subject to the applicable transportation agreement and billing procedures.
How long do you have to dispute freight reclassification?
Dispute deadlines vary by carrier, contract, and applicable rules. Review the carrier’s billing procedures promptly, request supporting documentation, and submit any dispute within the required timeframe.
Do NMFC item numbers ever change?
Yes. NMFTA periodically updates commodity descriptions, item numbers, and classification requirements. Businesses should review frequently shipped products when changes occur to help prevent outdated classification information from affecting quotes.
Where can I verify my LTL freight class?
You can research classification requirements through NMFTA resources, including ClassIT+, or consult your carrier or transportation provider. Verify the commodity’s NMFC item number and any applicable density or special classification requirements.
Choose the right freight class with confidence
LTL classification can seem complicated at first, but understanding the fundamentals makes LTL shipping far more predictable. Once you know how carriers evaluate density, handling, stowability, and liability, it’s easier to understand why shipments receive different classifications and how those classifications affect shipping costs.
The best way to avoid unexpected charges is to focus on the information you can control. Accurate weights, dimensions, commodity descriptions, and packaging details help carriers generate more reliable quotes while reducing the likelihood of freight reclassification.
If you’re ever unsure about a shipment’s classification, it’s worth asking questions before the freight is picked up. Verifying the details upfront is almost always easier than resolving billing adjustments after the shipment is already in transit. An experienced shipping partner can help verify your shipment information, identify the appropriate freight class, and improve quote accuracy before your shipment ever reaches the carrier’s network.
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