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Shipment Density

Also known as freight density · pallet density · pounds per cubic foot freight · density for freight class · PCF · LTL density calculator · class by density

ρ=mV\rho = \frac{m}{V}

Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!

See also
Density — The same relation as general physics states it, with the rest of its unit family.DIM Divisor as a Density — The density a parcel carrier's divisor represents — the figure this one has to beat.Cube-Out Crossover Density — The density at which the equipment carrying it runs out of room before payload.Chargeable Weight — For parcels, the density test decides which weight ends up on the invoice.

Learning zone

Density is mass divided by volume, and there is nothing special about the version on this page except what it is used for. In LTL freight, density is the number that drives classification, classification drives the rate, and the rate drives the bill. It is the most consequential single measurement in the trade, and it is also the one most often taken wrongly.

Measure the outside of the loaded skid. Not the product. Not the cartons. The outside dimensions of the whole assembled unit, including the pallet underneath it and any overhang past the pallet edges, because that is the space the trailer actually loses. A skid that overhangs by two inches on each side is four inches wider in every load plan for the rest of its journey. Include the pallet's weight too — 15 to 25 kg of wood is a real part of what the carrier hauls.

The NMFTA publishes a density guideline openly: a bracket table running from 50 lb/ft³ and up at class 50 down to under 1 lb/ft³ at class 500. It is genuinely public and it is genuinely useful for a first estimate. It is also not the classification. The NMFC itself is a proprietary publication, the item covering your commodity may not be density-based at all, and where it is, density is only one of four characteristics the classification considers — the others being stowability, handling and liability. A guideline bracket tells you roughly where you will land. It does not tell you what your freight classes as, and quoting it as though it did is how shippers end up with reclassification bills.

The other thing density tells you is whether dimensional weight can hurt you. A 139 divisor is 12.43 lb/ft³ and a 166 divisor is 10.41 lb/ft³. Freight above about 12.5 lb/ft³ will essentially never pay a dimensional-weight penalty on a 139 divisor, and no amount of packaging work will lower a parcel bill for it. Freight below it will, on every shipment, and packaging work pays immediately. That single comparison decides where a shipper's effort is worth spending.

Density is also one of the few freight levers a shipper controls outright. Taller stacks, less void fill, nested product, a carton sized to the goods rather than to the shelf — every one of those raises density, and raising density can lower the class and the chargeable weight at the same time. It is unusual in logistics to find a change that improves two independent things at once, which is why the density number is worth measuring properly rather than estimating.

Shipment Density
ρ=mV\rho = \frac{m}{V}
mρ = m / VV
Where
  • ρ\rho= Shipment density (kg/m³)
  • mm= Shipment weight (kg)
  • VV= Shipment volume (m³)
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