The rating system was built for weight. You are shipping air.
Freight class is substantially a density calculation, and empty packaging is the least dense freight most carriers handle. Understanding that one fact changes how you buy boxes more than any price negotiation will.
Price a lane
Origin, destination, size and count — we will quote every mode side by side.
That gap is the entire argument for banding everything flat before it leaves the yard.
Density first, then four other factors
The National Motor Freight Classification assigns commodities to one of eighteen classes from 50 to 500. Density does most of the work, but the system formally considers four characteristics: density, stowability, handling and liability. For corrugated packaging, density dominates and the other three rarely move the answer.
Calculate density by dividing weight in pounds by volume in cubic feet, using the outside dimensions of the shipping unit including the pallet. A pallet of knocked-down 18-inch double-wall cubes might weigh 280 lb and occupy 48 × 40 × 60 inches — that is 66.7 cubic feet, so 4.2 lb per cubic foot, landing it around class 200.
Reclassification, and why it hurts here
Carriers re-measure. If their dimensioner disagrees with your declared density, the shipment is reclassified and re-rated, usually upward, with an inspection fee attached. On dense freight the margin for error is wide. On packaging, where a few inches of shrink-wrap bulge changes the cubic feet materially, it is narrow.
The practical defence is to declare conservatively, wrap tightly without crushing the corners, and keep the pallet square. A load that bulges past the deck edge invites both reclassification and damage.
Where class stops mattering
Above roughly fourteen pallets you are on partial or full truckload pricing, which is negotiated per lane rather than rated by class. That transition is why buying more can cost less in total, and it is the single most useful thing to know about freight on this material.
Why empty packaging rates so badly.
LTL pricing keys off density. Knocked-down corrugated weighs almost nothing and occupies a full pallet position, so it lands near the expensive end of a scale designed around weight.
| Class | Density | Typical commodity | Where packaging sits |
|---|---|---|---|
| 50 | 50+ lb/ft³ | Bricks, steel bar | Rarely packaging |
| 55 | 35 – 50 | Hardwood flooring | Dense palletised goods |
| 60 | 30 – 35 | Car accessories | Heavy cartoned goods |
| 65 | 22.5 – 30 | Bottled beverages | Full case packs |
| 70 | 15 – 22.5 | Food in cartons | Typical dense distribution |
| 85 | 12 – 15 | Crated machinery | Palletised assemblies |
| 92.5 | 10.5 – 12 | Computers, monitors | Cushioned electronics |
| 100 | 9 – 10.5 | Boat covers, canvas | Light bulky goods |
| 125 | 7 – 8 | Small appliances | Void-filled cartons |
| 150 | 6 – 7 | Auto sheet metal | Erected boxes start here |
| 175 | 5 – 6 | Clothing, couches | Knocked-down heavy board |
| 200 | 4 – 5 | Aircraft parts | Knocked-down double wall |
| 250 | 3 – 4 | Mattresses, plasma TVs | Knocked-down single wall |
| 300 | 2 – 3 | Wood cabinets, tables | Erected gaylords |
| 400 | 1 – 2 | Deer antlers | Erected light bulk |
| 500 | < 1 | Gold dust, ping-pong balls | Loose void fill |
Note the two rows that matter here: knocked-down board is class 150 – 250, erected containers are class 300 – 400. That gap is the entire argument for banding everything flat.
What actually fits in the truck.
Every cube figure we quote is calculated against these, at a realistic 72% packing efficiency rather than a theoretical 100%.
| Unit | Inside dimensions | Volume | Pallet positions | Payload | Note |
|---|---|---|---|---|---|
| 53' dry van | 630" × 100" × 110" | 3,489 ft³ | 26 | 45,000 lb | Our standard outbound unit |
| 48' dry van | 576" × 99" × 108" | 3,100 ft³ | 24 | 44,000 lb | Older fleet, still common on LTL |
| 28' pup | 330" × 100" × 108" | 1,750 ft³ | 12 | 22,000 lb | LTL linehaul segment |
| 26' straight truck | 306" × 96" × 96" | 1,700 ft³ | 12 | 10,000 lb | Liftgate deliveries to sites without docks |
| 40' container | 474" × 92" × 94" | 2,390 ft³ | 20 | 59,000 lb | Export; corrugated avoids ISPM 15 |
| 40' high cube | 474" × 92" × 106" | 2,694 ft³ | 20 | 58,000 lb | Preferred for low-density freight |
Ten conversions we use every day.
None of these are difficult. All of them are regularly got wrong, usually by a factor of 1,728.
| From | To | Factor | Worked example |
|---|---|---|---|
| Cubic inches | Cubic feet | ÷ 1,728 | 48 × 40 × 36 = 69,120 in³ = 40.0 ft³ |
| Square inches | Square feet | ÷ 144 | 13,528 in² = 93.9 ft² |
| Pounds per ft² | Board weight | × area in ft² | 93.9 ft² × 0.55 = 51.7 lb |
| Pounds | Kilograms | × 0.45359 | 51.7 lb = 23.5 kg |
| Inches | Millimetres | × 25.4 | 48" = 1,219 mm |
| Cubic feet | Cubic metres | × 0.02832 | 40.0 ft³ = 1.13 m³ |
| Short tons | Metric tonnes | × 0.90718 | 11,800 tons = 10,705 tonnes |
| Loose OCC volume | Weight | × 80 lb/yd³ | 40 yd³ ≈ 3,200 lb |
| Baled OCC volume | Weight | × 700 lb/yd³ | 2 yd³ bale ≈ 1,400 lb |
| Trailer volume (53') | Usable | × 0.72 | 3,489 ft³ → 2,512 ft³ |
Seven things about your dock that change the quote.
Declared before the quote these are free to plan around. Discovered on delivery day they are the single most common reason a cheap quote becomes an expensive invoice.
| Item | Specification | Why it matters |
|---|---|---|
| Dock height | 48 – 52" typical | Below 44" a standard trailer needs a leveller or a ramp |
| Dock leveller capacity | 20,000 – 30,000 lb | Loaded gaylords on a pallet truck approach the limit |
| Door width | 8 – 9 ft | Double-stacked knocked-down bundles are wide |
| Apron depth | 100 – 130 ft | A 53-foot trailer needs room to square up |
| Liftgate requirement | If no dock | Add $75 – $150; declare it before the quote, not after |
| Receiving window | 3-day window ideal | Lets us consolidate; worth more than a volume discount |
| Forklift availability | 3,000 lb minimum | A loaded gaylord plus pallet exceeds many electric walkies |
Freight class, specifically.
Who assigns the class — me or the carrier?
You declare it on the bill of lading and the carrier verifies it. Getting it wrong in either direction causes problems: understating invites reclassification fees, overstating means you simply pay more than you needed to.
Does the pallet count in the density calculation?
Yes. Use the outside dimensions and total weight of the complete handling unit, pallet and wrap included. Forgetting the pallet is a common way to understate volume and get reclassified.
Can I get a lower class by packing tighter?
Genuinely, yes — density is the dominant factor, and knocked-down, nested, tightly banded board is materially denser than loosely stacked board. It is one of very few situations where better packing directly lowers a published rate.
What about dimensional weight on parcel?
Parcel carriers use dimensional weight rather than NMFC class, dividing cubic inches by a divisor. The underlying problem is identical: you pay for space, not weight, and empty packaging is mostly space.
Should I just use truckload for everything?
If you can take fourteen-plus pallets at a time, usually yes. If you cannot, a standing order held in our yard and released in truckload drops gives you the same economics without the storage.