Freight density is total weight in pounds divided by total cube in cubic feet — and since the NMFC's July 19, 2025 overhaul, that one number sets the class for most LTL freight. The formula is short: length × width × height in inches, ÷ 1,728, then weight ÷ cube. What trips shippers up is a feel for the answer — is a pallet of books dense or light? Does a boxed sofa really rate four tiers above a crated engine? Below are 20 real shipments worked out end to end: dims, weight, cube, density and class for each, spanning every one of the 13 density tiers.
How do you calculate freight density?
Three steps, in the order the carrier's dimensioner does them. Measure the extreme points of the handling unit as it will actually ship — pallet, overhang and shrink wrap included; a standard 48×40 pallet adds about 5.5 inches and 40 lb. Cube it: L × W × H in inches, divided by 1,728, gives cubic feet. Divide the weight by that cube. Then read the class off the current 13-tier scale (the step-by-step guide covers multi-pallet math and the traps):
| Density (lb/ft³) | Class | Density (lb/ft³) | Class |
|---|---|---|---|
| 50 or more | 50 | 8 to under 10 | 100 |
| 35 to under 50 | 55 | 6 to under 8 | 125 |
| 30 to under 35 | 60 | 4 to under 6 | 175 |
| 22.5 to under 30 | 65 | 2 to under 4 | 250 |
| 15 to under 22.5 | 70 | 1 to under 2 | 300 |
| 12 to under 15 | 85 | Under 1 | 400 |
| 10 to under 12 | 92.5 |
20 freight density examples, worked out
Every row below is a realistic handling unit: palletized loads are measured over the pallet (5.5 in and 40 lb of it are in the numbers); items marked floor ship as their own carton or crate. Dims are inches, cube is L×W×H÷1,728, density is weight÷cube.
| Shipment | Dims (in) | Weight (lb) | Cube (ft³) | Density | Class |
|---|---|---|---|---|---|
| Ceramic floor tile, boxed on one pallet | 48×40×26 | 1,860 | 28.9 | 64.4 | 50 |
| Steel bolts & fasteners, cartons on a low pallet | 48×40×21.5 | 1,310 | 23.9 | 54.8 | 50 |
| Solid oak flooring, 24 cartons | 48×40×32.5 | 1,384 | 36.1 | 38.3 | 55 |
| Water-softener salt, 48 × 40-lb bags | 48×40×45.5 | 1,960 | 50.6 | 38.8 | 55 |
| Bottled water, 72 cases of 16.9-oz | 48×40×53.5 | 2,056 | 59.4 | 34.6 | 60 |
| Copy paper, 40 cartons (400 reams) | 48×40×59 | 2,120 | 65.6 | 32.3 | 60 |
| Canned tomatoes, 98 cases | 48×40×51.5 | 1,610 | 57.2 | 28.1 | 65 |
| Rebuilt V8 engine, drained, in a crate | 42×36×36 | 640 | 31.5 | 20.3 | 70 |
| Books, 30 cartons | 48×40×35.5 | 850 | 39.4 | 21.5 | 70 |
| Benchtop lathe, crated | 40×30×30 | 300 | 20.8 | 14.4 | 85 |
| Knock-down shelving, packed flat | 48×40×29.5 | 440 | 32.8 | 13.4 | 85 |
| Top-load washing machine, boxed (floor) | 27×27×43 | 190 | 18.1 | 10.5 | 92.5 |
| Mixed consumer goods, full warehouse pallet | 48×40×60.5 | 560 | 67.2 | 8.3 | 100 |
| Upright vacuums, 12 cartons | 48×40×44.5 | 400 | 49.4 | 8.1 | 100 |
| Folded apparel, 20 cartons | 48×40×53.5 | 440 | 59.4 | 7.4 | 125 |
| Gas grill, boxed (floor) | 57×24×25 | 95 | 19.8 | 4.8 | 175 |
| Queen mattress, boxed flat (floor) | 80×60×12 | 95 | 33.3 | 2.8 | 250 |
| Assembled 3-seat sofa, boxed (floor) | 84×38×35 | 190 | 64.7 | 2.9 | 250 |
| Kayak, boxed (floor) | 124×30×14 | 55 | 30.1 | 1.8 | 300 |
| Foam mattress toppers, one carton (floor) | 48×24×24 | 14 | 16.0 | 0.9 | 400 |
Three patterns worth internalizing. Dense freight is short. The class 50–55 loads all sit under 46 inches — tile stops at 26 — because floors, forklifts and carton crush strength give out long before a pallet cubes out. Weight alone tells you nothing. The 190-lb washing machine rates class 92.5 while the 190-lb boxed sofa rates 250 — same weight, 3.6× the cube. The middle of the chart is where packaging decides. Between 4 and 15 lb/ft³ the tiers are only 2 lb/ft³ wide, so the flat-packed shelving rides at 85 while the same product assembled would rate 175 — the exact swing worked through in the packaging guide.
One example in full: the 190-lb washing machine
Here's the arithmetic behind one row, exactly as a rater would run it. The boxed washer measures 27 × 27 × 43 inches and weighs 190 lb, shipping as its own carton.
Cube: 27 × 27 × 43 = 31,347 in³. Divided by 1,728: 18.1 ft³. Density: 190 ÷ 18.1 = 10.5 lb/ft³. On the 13-tier scale, 10 but less than 12 is class 92.5.
Now watch what handling does to it. Strap that washer to a standard pallet and the unit becomes roughly 48 × 40 × 48.5 at 230 lb: 53.9 ft³, 4.3 lb/ft³ — class 175, three tiers up, because the pallet's footprint is mostly air around a 27-inch box. This is the single most common self-inflicted wound in LTL: palletizing one mid-size carton without cubing the result first. For a shipment of several different pallets, the same math runs once over the totals — sum the cubes, sum the weights, divide once.
The 21st shipment: the one density can't classify
Work a laced pallet of passenger tires like the rows above and you get 48 × 40 × 45.5 at about 190 lb: 50.6 ft³, 3.8 lb/ft³ — class 250 territory on the chart. Tires don't rate there. They're the classic commodity-rated exception: the long-standing anchor is class 70, with broker listings running roughly 60–85 depending on the item and sub. Density-rate a tire shipment off the chart and the correction arrives as a rebill.
Tires aren't alone — some items still carry fixed classes or handling, stowability and liability provisions that override the density table. The rule that keeps invoices matching quotes: run the density math, then confirm the NMFC item before anything hits the BOL. If the item is density-rated — as most freight now is under the 2025 changes — the chart is the answer; if it isn't, the item wins.
What the boundary rows teach
Look at where several examples sit: the books at 21.5 against the 22.5 boundary, the vacuums at 8.1 against 8, the lathe at 14.4 against 15. Freight lives near tier edges more often than not, and the edges are where money moves — a load at 8.1 lb/ft³ that gains one inch of height slides under 8 and re-rates from class 100 to 125. Two habits follow. Measure the built handling unit, not the plan: roughly 1 in 4 LTL shipments gets reweighed or re-measured at the dock, and a re-rate plus inspection fee costs far more than a tape measure. And when you're close to a boundary from below, treat it as an invitation: an inch off the load height or a tighter carton is often worth a full tier — the cheapest rate reduction in freight.