Essential
Freight Density Calculator
Freight density is weight per unit volume — kg/m³ or lb/ft³ — and it is the number carriers use to decide whether a shipment is billed on its actual weight or on the space it takes up. Enter a total weight and volume to get both figures, and see whether your cargo is dense (heavy for its size) or light and bulky.
CBM, e.g. from the CBM Calculator
Density (metric)
250.00 kg/m³
Density (imperial)
15.61 lb/ft³
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Results are indicative only. Rates, transit times, classifications, and charges vary by carrier, lane, and contract. For binding quotes, post a request on CargoLinked or contact your forwarder.
How it works
Density is a straightforward ratio: total shipment weight divided by total shipment volume. This calculator returns the result in both metric (kg/m³) and imperial (lb/ft³), since forwarders and carriers in different regions quote and think in different units for the same underlying figure.
Density is why two shipments of identical weight can cost very different amounts to ship. A dense shipment (high kg/m³) is compact for its weight, so it is usually billed on actual (gross) weight. A light, bulky shipment (low kg/m³) takes up disproportionate space relative to its weight, so carriers instead bill it on a volumetric weight calculated from its dimensions — see the Air Chargeable Weight and Road Dimensional Weight calculators for that specific math.
In US domestic LTL (less-than-truckload) trucking, density also feeds into freight class (NMFC) — carriers commonly use a published density-to-class scale where lower density maps to a higher, more expensive class. Class bands and the exact NMFC edition in use vary by carrier and commodity, so this calculator reports density only; it does not assign a freight class.
Density (kg/m³) = Weight (kg) ÷ Volume (m³); lb/ft³ = kg/m³ × 0.06242796
Worked example
500 kg of cargo occupying 2 m³
- Divide weight by volume500 ÷ 2 = 250 kg/m³
- Convert to imperial250 × 0.06242796 ≈ 15.61 lb/ft³
Density: 250 kg/m³ (≈15.61 lb/ft³)
Frequently asked questions
What is freight density and why does it matter?
Freight density is a shipment's weight divided by its volume, expressed as kg/m³ or lb/ft³. It matters because carriers use it to decide how to bill a shipment: dense cargo is usually billed on actual weight, while light, bulky cargo is usually billed on a volumetric weight instead, which can be significantly higher than the actual weight for low-density freight.
How does density affect LTL freight class?
In US LTL trucking, carriers commonly assign an NMFC freight class partly based on density, with lower-density freight generally landing in a higher, costlier class. The exact density-to-class bands vary by carrier, commodity, and NMFC edition, so treat this as a general pattern rather than a fixed table — ask your carrier or forwarder for the specific class your cargo falls into.
What is the difference between freight density and stowage factor?
Density is a property of the cargo itself — its weight per unit volume, independent of how it is packed. Stowage factor describes packing efficiency inside a container or trailer — how much of the available space the cargo actually fills once loaded, which depends on shape and packing method as much as density. Use the Stowage Factor Checker once you know how your cargo will actually be loaded.
Does dense or light cargo cost more to ship?
Neither is inherently cheaper — cost depends on which figure a carrier bills against. Very dense cargo (e.g. machinery parts) is billed on actual weight and can be expensive simply because it is heavy. Very light, bulky cargo (e.g. empty packaging or foam products) is often billed on volumetric weight, which can push the billed weight well above the actual scale weight. Mid-density cargo is usually the most cost-efficient to ship per unit of actual weight.
How is density different from chargeable weight?
Density (kg/m³) is a rate describing how compact a shipment is. Chargeable weight is the actual number a carrier bills you for — the higher of your gross weight and a volumetric weight derived from your dimensions using a mode-specific divisor. Low density tends to push chargeable weight above gross weight; use the Air Chargeable Weight or Road Dimensional Weight calculators to get that billed figure directly.
Related tools
Estimates & assumptions
- Reports density only — this calculator does not assign an NMFC freight class or any carrier-specific classification.
- Density-to-class relationships and stowage conventions vary by carrier, mode, and region; confirm specifics with your forwarder before pricing a shipment on density alone.
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