LTL pricing looks like it runs on weight and freight class, and for most shipments it does. But every carrier's tariff hides a second pricing system that switches on when your freight occupies too much of the trailer floor: the linear foot rule. Cross the threshold and the class rate you quoted stops applying — the carrier re-rates the shipment on the space it blocks, often at a sharply higher figure. This guide explains how linear feet are measured, where the thresholds sit, and what to do when your shipment is near one.
What linear feet actually measure
Linear feet are the length of trailer floor your shipment occupies, measured front to back along the trailer — regardless of how much of the trailer's width or height it fills. A single pallet in the middle of the floor and a wall of freight spanning both sides count the same way: from the first point of freight to the last, down the length of the trailer.
The math follows from the trailer's geometry. A dry van's interior is about 98.5 inches wide, so standard 48×40 pallets fit exactly two abreast. Each row of one or two pallets occupies 48 inches — 4 linear feet — of floor:
| Standard 48×40 pallets | Rows (2 abreast) | Linear feet |
|---|---|---|
| 2 | 1 | 4 ft |
| 6 | 3 | 12 ft |
| 10 | 5 | 20 ft |
| 16 | 8 | 32 ft |
| 26 | 13 | 52 ft (a full 53' van) |
The general formula, for any footprint: pallets per row = ⌊trailer width ÷ pallet width⌋, rows = ⌈quantity ÷ pallets per row⌉, linear feet = rows × pallet length ÷ 12. The Linear Feet Calculator runs this per item group, handles double-stacking, and flags the thresholds below automatically.
The rule: where class pricing stops
Most LTL carriers publish a linear foot rule in their rules tariff. The wording differs, but the shape is consistent: once a shipment exceeds a set number of linear feet — commonly somewhere between 10 and 16, depending on the carrier — it no longer qualifies for normal class-based rating. Instead the carrier applies volume or "cube" pricing, and a widely used convention rates the shipment as if it weighed 1,000 lb per linear foot, even when the actual freight is far lighter.
The logic is simple economics. An LTL carrier sells the same trailer to many shippers at once; a light, bulky shipment that blocks 14 feet of floor prevents the carrier from selling that floor to anyone else. The linear foot rule reprices such freight from "what it weighs" to "what it displaces" — the same idea that gives air freight its volumetric weight and ocean LCL its revenue ton.
Two adjacent tariff provisions often travel with the rule. Cubic capacity rules trigger on volume instead of footage — a common form is "750 cubic feet or more at a density under 6 lb/ft³". And overlength or excessive length fees hit single pieces past a set length (frequently 8 or 12 feet) even when the total shipment is small. If your freight is long, light, or both, read all three sections of the carrier's rules tariff, not just the linear foot one.
A worked example
Say you ship 8 pallets of foam packaging, 48×40 inches, 60 inches tall, 350 lb each — 2,800 lb all in. Loaded two abreast they occupy 4 rows: 16 linear feet. At a density of about 5.3 lb/ft³ the class table says Class 125, and a class-rated quote might look pleasantly cheap. But 16 linear feet exceeds essentially every carrier's threshold. Rated at the 1,000 lb-per-foot convention, the shipment prices as 16,000 lb of freight — nearly six times its scale weight. The class quote was never the real price.
Same freight, stackable, loaded two high: 2 rows, 8 linear feet, under every common threshold — normal class pricing applies again. Whether your freight can be stacked or turned is frequently worth more than any discount percentage in the rate negotiation.
Staying under the threshold
Stack when the freight allows it. Double-stacking halves rows, and rows are the whole game. Crush-sensitive freight can often still be stacked with a layer of corner boards and a top cap.
Turn the pallets. Rotating 48×40 pallets so the 40-inch side runs down the trailer cuts each row from 4 ft to 3.33 ft — 26 pallets drop from 52 to about 43 linear feet. Confirm the carrier and your forklifts handle turned entry; the Trailer Load Calculator shows both patterns side by side.
Split or reconsolidate. Two 8-foot shipments on different days can price better than one 16-foot shipment — and past roughly 12–16 feet it's often cheaper to buy volume LTL deliberately, or book a partial truckload, than to fall into the rule accidentally.
Declare honestly. Carriers measure. Dimensioners at the dock capture length, width and height on every handling unit, and a shipment that quoted 8 feet but occupies 14 will be re-rated after pickup, when you have no negotiating position left.
Quick checklist before you book
Compute your linear feet with the actual loading plan, not the pallet count alone. Check the specific carrier's rules tariff for its threshold — 10, 12 and 16 ft variants all exist in the market. If you're within 2 feet of the line, price the stacked and turned alternatives. And if the shipment clearly exceeds the threshold, get a volume or partial-truckload quote upfront instead of letting the rule surprise you on the invoice.