What freight class is
The National Motor Freight Classification (NMFC) system assigns every LTL shipment a class from 50 to 500. Lower classes are denser, more compact freight that's cheaper to ship; higher classes are bulkier, lighter freight that takes up trailer space without adding much weight. Class is one of the main inputs carriers use to price an LTL shipment — alongside weight, distance, and accessorial requirements.
The density-based scale
For many general commodities, class is determined by density alone, using a 13-tier scale:
| Density (PCF) | Class |
|---|---|
| Under 1 | 400 |
| 1 – under 2 | 300 |
| 2 – under 4 | 250 |
| 4 – under 6 | 175 |
| 6 – under 8 | 125 |
| 8 – under 10 | 100 |
| 10 – under 12 | 92.5 |
| 12 – under 15 | 85 |
| 15 – under 22.5 | 70 |
| 22.5 – under 30 | 65 |
| 30 – under 35 | 60 |
| 35 – under 50 | 55 |
| 50 and above | 50 |
Current as of NMFC Docket 2025-1 (effective July 19, 2025), which introduced the 65, 60, 55, and 50 classes.
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 carrier or their classification system makes the actual determination at pickup or during audit, and that's the number that governs the final invoice. 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.
Get an estimated class for your actual shipment.
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