LTL shipping is priced by freight class, weight and lane using a tariff that sets a rate per hundred pounds (cwt) for each class. Class 50 freight may be rated at $20 to $30 per cwt. Class 300 on the same lane can run $150 or more. Getting the class right is one of the most direct ways to control what you actually pay, more direct than most rate negotiations.
What actually sets the per-cwt rate?
Carriers maintain tariffs with base rates per cwt by class. Contract shippers get percentage discounts off those base rates. The actual charge works out to weight divided by 100, times the rate per cwt, times one minus the discount. A 500 lb class 70 shipment at $50 per cwt with a 60 percent discount comes to 5 cwt times $50 times 0.40, or $100.
What if my shipment is too small to matter?
Carriers apply a minimum charge floor, so small shipments that calculate below it pay the minimum anyway. Some tariffs also use deficit pricing: if pricing at a higher weight and a lower rate produces a bigger total than your actual weight and class would, the carrier bills the deficit figure instead.
What happens when a carrier reclassifies you?
If a carrier reweighs or remeasures and finds a different density, they reclassify the shipment and issue a billing adjustment, often after delivery rather than before. Repeated reclassifications on a high-volume account are usually a sign that something in the measurement or packaging process needs fixing, not just bad luck.
How do you actually lower your class?
- Cut packaging volume. Air space lowers density and pushes the class up.
- Use compact pallets, stack tightly, and keep height in proportion to the footprint.
- Look up the NMFC item number. The density-based class is sometimes higher than the specific item class, which saves money.
- Consolidate shipments when possible. Two lighter loads combined into one denser shipment can drop the class.
Run the numbers on any of these changes with the Freight Class Calculator before you commit to new packaging, since a small dimension change can move a shipment a full class band.
See the math on your own shipment
Enter weight and dimensions and see the class, density and a ballpark cost update instantly.