Understanding Freight Classes and How They Affect Shipping Costs A Practical Guide for Smarter Shipping

If you’re shipping goods via LTL (less-than-truckload) freight, you’ve probably come across terms like “freight class” or “NMFC code.” Understanding freight classes is essential because they directly impact your shipping costs, carrier selection, and risk of freight reclassification charges.

Let’s break down what freight classes are, how they’re determined, and how they affect your bottom line so you can ship smarter.

Key Takeaways

• Freight classes categorize shipments based on weight, size, density, handling, and liability.
• Your shipment’s class determines how much you’ll pay for LTL freight services.
• Incorrect freight class assignments can lead to costly billing adjustments.
• Accurately classifying your freight helps you avoid delays and extra fees.

1. What Is Freight Class?

Freight class is a standardized rating system used in the U.S. for LTL shipments. Managed by the National Motor Freight Traffic Association (NMFTA), it groups freight into 18 classes (from 50 to 500).

Key factors that determine freight class:

• Density (weight per cubic foot) — Heavier, denser items usually fall in lower, cheaper classes.
• Stowability — How easily items fit together in a truck.
• Handling — Fragility, size, and whether special equipment is needed.
• Liability — Risk of damage, theft, or harm during transit.

2. How Freight Class Affects Shipping Costs

Freight class is one of the biggest factors in your LTL shipping cost.

What to know:

• Lower class (e.g., 50, 55) — Dense, easy-to-ship items (like bricks or steel rods) that cost less to ship.
• Higher class (e.g., 400, 500) — Lightweight, bulky, or fragile goods (like ping pong balls or furniture) that cost more.

Accurate classification ensures you’re charged the correct rate up front and helps you avoid reclassification charges later.

3. How to Determine the Right Freight Class

Steps to get it right:

1. Measure and weigh your shipment — Calculate its density by dividing weight by cubic feet.
2. Check NMFC codes — These codes help identify the correct class for specific goods.
3. Use carrier or 3PL tools — Many offer freight class calculators or guidance.
4. Consult your freight broker or carrier if in doubt.

Getting it right at the start saves time, money, and hassle.

4. Tips for Managing Freight Class Costs

• Package items efficiently to increase density.
• Consolidate shipments when possible to lower the overall class.
• Document everything (photos, measurements, weight) to support your declared class if challenged.
• Ask carriers about class exceptions — Some items qualify for lower classes under specific conditions.

Small changes in packaging and preparation can lead to big savings on shipping costs.

Conclusion

Understanding freight classes helps you take control of your shipping costs and avoid surprises on your freight bills. By classifying shipments accurately and working closely with carriers or brokers, you can keep your logistics efficient and cost-effective.