What you need before you start
Grab a tape measure and a scale. You need the total shipping weight and three dimensions, length, width and height, measured on the shipment as it will actually sit on the truck, pallet and packaging included. Round every dimension up to the next whole inch. Carriers will remeasure, and rounding down just invites a reclass later.
Step-by-step: weight and volume to PCF
- Weigh the full shipment, including pallet and packaging.
- Measure length, width and height in inches at the widest points.
- Convert to cubic feet: multiply length by width by height, then divide by 1,728.
- Divide the weight in pounds by the cubic feet figure. That result is density in PCF.
- Match the PCF number against the density table below to find the class.
Worked example
A 400 lb shipment measures 48 x 40 x 48 inches. Volume: 48 × 40 × 48 ÷ 1,728 = 53.33 cubic feet. Density: 400 ÷ 53.33 = 7.5 PCF. That figure falls in the 7 to 8 PCF row, which is class 125. Run the same shipment through the Density Calculator to double-check the arithmetic in a few seconds.
Why density drives LTL pricing
LTL trailers are constrained by both weight and cubic capacity. Light, bulky freight fills space without contributing much weight, which cuts into what a carrier can load on a given trailer. High-density freight lets carriers load more weight per cubic foot, and they price that advantage into lower class rates. A 10 PCF shipment (class 92.5) costs less per hundred pounds than a 4 PCF shipment (class 200) of the same weight.
Common measurement mistakes
The most frequent error is measuring the product instead of the finished, palletized load, which understates both volume and weight. A close second is averaging piece-by-piece density on a multi-piece shipment instead of totaling cubic feet and weight across every piece first. The carrier bills the whole shipment on one bill of lading, so the density calculation has to treat it as one unit too.
A third mistake shows up on irregular or stacked freight: measuring the smallest bounding box instead of the true outer dimensions the trailer actually has to accommodate. If a shipment tapers, overhangs a pallet edge, or stacks unevenly, use the widest point on each axis, not an average. Carriers measure the space freight occupies, not the space it would occupy if it were packed more efficiently than it actually is.
Density table quick reference
| Density (PCF) | Class |
|---|---|
| 50+ | 50 |
| 35 to 50 | 55 |
| 22.5 to 30 | 65 |
| 15 to 22.5 | 70 |
| 10.5 to 12 | 92.5 |
| 9 to 10.5 | 100 |
| 7 to 8 | 125 |
| 6 to 7 | 150 |
| 4 to 5 | 200 |
| Under 1 | 500 |
Skip the manual math
Enter weight and dimensions once, and let the tool return density, class and a cost estimate.