Two identical-weight pallets leave the same dock for the same city. One is rated class 70, the other class 125. The second invoice arrives 30–60% higher. Nothing about distance, fuel or service changed — only the class. Here's the machinery behind that difference, and the legal ways to point it in your favor.
Where class enters the rate
LTL pricing starts from a base rate table (carrier-published or CzarLite-style): for each lane and weight break, a rate per hundred pounds (CWT) is listed per class. Discounts, FAK agreements, fuel surcharges and accessorials all multiply on top, but the class row you start in scales everything downstream. Illustrative shape of a real table, 1,000 lb on a regional lane:
| Class | Base rate / CWT | Linehaul before discount | vs class 70 |
|---|---|---|---|
| 70 | $38 | $380 | — |
| 85 | $45 | $450 | +18% |
| 100 | $52 | $520 | +37% |
| 125 | $61 | $610 | +61% |
| 175 | $78 | $780 | +105% |
Illustrative numbers to show the shape — every carrier's table and discount differs. The ratios are typical of published class scales.
How shippers end up a class too high
- Stale defaults: a class keyed into the TMS years ago — especially dangerous since the 2025 NMFC re-draw moved real freight both directions.
- Air in the packaging: oversized cartons and tall void fill lower density; density picks the class. Two inches of unnecessary height on a 48×40 pallet is ~4 ft³ of billable air.
- Guessing conservative: declaring 125 "to be safe" doesn't prevent inspections — it just guarantees overpayment on every clean shipment.
How carriers end up re-rating you higher
Terminals photograph, weigh and dimension nearly every handling unit. If the machine reads 6.9 lb/ft³ and the BOL says class 70 (15+ lb/ft³), the shipment is re-rated to the measured class and an inspection fee is added — then the invoice dispute consumes an hour of someone's week. The fix is unglamorous: measure after the pallet is wrapped, compute the density, and put the machine's answer on the BOL first.
Five legal levers that lower the bill
- Chase the boundary. Class steps at 8, 10, 12 and 15 lb/ft³. If you're 0.3 pcf short of the next band, shorter cartons or one fewer layer of foam changes the invoice — the calculator flags this automatically.
- Consolidate handling units. Two half-height pallets pool into one denser shipment; pooled density is what's rated.
- Negotiate an FAK around your real mix, re-checked against post-2025 classes — an FAK negotiated on 2024 numbers may now be paying the carrier.
- Fix the paperwork. Item number + sub, real dims, real weight. Clean BOLs get inspected less and disputed never.
- Audit invoices quarterly. Re-rate a sample with measured density; recurring class bumps on one SKU mean its packaging — or its saved class — needs work.