Understanding Freight Class

Freight class is an important part of an LTL quote — and one of the most misunderstood.

What freight class is

The National Motor Freight Classification (NMFC) uses freight classes from 50 to 500. For density-based provisions, lower classes correspond to denser freight and higher classes to less-dense freight. Class is one input to an LTL quote alongside weight, distance, services, and other shipment details; it does not determine price by itself.

The density-based scale

For many general commodities, class is determined by density alone, using the current 13-sub density scale:

The 13-sub density structure was introduced by NMFC Docket 2025-1, effective July 19, 2025. NMFC updates continue, so verify the applicable commodity item and current classification requirements before booking.

Density isn't the only factor

Some commodities have their own specific NMFC item, assigned based on handling requirements, stowability, liability (theft or damage risk), or other characteristics defined for that item — not purely on density. Fragile goods, used or reconditioned equipment, high-value electronics, and loose or unpackaged freight are common examples where an item-specific classification can differ from what density alone would suggest. See freight class by commodity for why the product name alone rarely settles which situation you're in.

Why "estimated" matters

An estimated freight class based on density is genuinely useful for planning and for the quote conversation — but it's an estimate, not the carrier's final word. The applicable classification is determined under the governing NMFC item and the carrier or quoting party's applicable rules; a later audit or inspection can reveal that the shipment was declared using the wrong class or shipment facts. If your estimate and the carrier's applied class don't match, that's usually where a post-pickup rate adjustment comes from.

What to do with an estimated class

• Use it to get a realistic quote range before you commit to a carrier.
• Mention it explicitly when requesting quotes, so the broker can flag early if they'd expect something different.
• For unusual or high-value commodities, ask your broker to confirm the applicable NMFC item rather than relying on density alone.

Sources: NMFC density scale via the NMFTA Help Center; NMFC Item 110, Sec. 8(d) via the NMFTA Help Center.