Freight Density Calculator
Enter shipment weight and volume to calculate freight density in kg/m³ and lb/ft³. Includes an indicative US NMFC freight class — useful for LTL pricing, carrier rate planning and identifying low-density cargo that may attract volumetric surcharges.
Enter shipment weight and volume to calculate freight density in kg/m³ and lb/ft³. Used to determine LTL freight class, compare shipment efficiency, and identify light-but-bulky cargo that may attract volumetric surcharges.
Formula
Freight Density = Shipment Weight ÷ Shipment Volume | kg/m³ × 0.0624 = lb/ft³
Freight density measures how much a shipment weighs per unit of space. Carriers use density to assess how efficiently cargo fills a trailer or container. Low-density cargo (bulky but light) typically incurs higher freight class ratings and volumetric surcharges.
Worked Example
Shipment: 500 kg gross weight · 2.0 m³ volume:
Density = 500 kg ÷ 2.0 m³ = 250 kg/m³
In lb/ft³ = 250 × 0.0624 = 15.6 lb/ft³
US NMFC class ≈ Class 70 (indicative)
A density of 250 kg/m³ is well above the "light freight" threshold. For comparison, a shipment of foam packaging material at 50 kg in 2 m³ would show 25 kg/m³ density — triggering higher LTL class rates and volumetric surcharges from most carriers.
FAQ
Frequently Asked Questions
Use this in your workflow
Use freight density to understand whether your cargo will attract volumetric surcharges, then use the Dimensional Weight Calculator to quantify the air freight impact. Feed the result into the Landed Cost Calculator to model the full import cost. Browse all Business Calculator Hub.
Worked example: lightweight foam packaging
A useful starting point before entering your own figures above.
| Item | Value |
|---|---|
| Shipment dimensions | 120 × 100 × 80 cm |
| Actual gross weight | 48 kg |
| Volume (1.2 × 1.0 × 0.8) | 0.96 m³ |
| Freight density (48 ÷ 0.96) | 50 kg/m³ (3.1 lb/ft³) |
| Indicative NMFC freight class | Class 250–300 (low density) |
| Implication | Volumetric surcharge likely |
Interpretation: at 50 kg/m³ (3.1 lb/ft³), this is low-density cargo. US LTL carriers typically assign Class 250–300 for densities below 4 lb/ft³, which attracts a significantly higher rate per cwt than denser goods. Improving packing density — for example, by compressing the foam insert — could shift the shipment to Class 100–150 and halve the freight rate.
Limitations
The NMFC freight class shown is indicative based on density alone. Actual freight class is determined by the carrier based on the full NMFC classification, which considers density, stowability, handling, and liability — not density alone. High-value, fragile, or hazardous goods may be classified differently. Always confirm the freight class with your carrier or 3PL before booking. These results are for planning purposes only.
When to use this calculator
- →Checking if your cargo will be subject to LTL volumetric surcharges in the US market
- →Comparing packing configurations to maximise cargo density and reduce freight class
- →Providing density data to freight brokers or 3PLs for accurate rate quoting
- →Identifying light-but-bulky shipments before committing to an air freight service
Frequently asked questions
What is freight density?
Freight density is weight divided by volume, expressed in kg/m³ or lb/ft³. Carriers use it to assess how efficiently cargo fills a vehicle or container. Low-density cargo typically attracts higher freight class ratings and volumetric surcharges.
Why do carriers care about freight density?
Vehicles have both a weight limit and a volume limit. Light, bulky cargo fills space without contributing weight revenue. To compensate, carriers apply volumetric pricing rules or higher freight classes for low-density shipments.
What is a good freight density for road freight?
US LTL carriers use NMFC freight classes from Class 50 (densest, cheapest) to Class 500. Most manufactured goods fall between Class 65 and Class 100, with densities of approximately 8–23 lb/ft³ (130–370 kg/m³).
How is freight density different from dimensional weight?
Freight density measures weight per unit volume (kg/m³) and is primarily used for US LTL freight class determination. Dimensional weight is used by air freight carriers and express couriers — it converts shipment volume into an equivalent weight using a divisor (5000 or 6000).
Does sea freight use density-based pricing?
LCL (Less than Container Load) sea freight is typically priced on the greater of actual weight (per tonne) or volume (per CBM), with a standard conversion rate of 1 CBM = 1 metric tonne for pricing. Density-based surcharges are more common in road (LTL) and air freight.
Can I reduce freight costs by improving density?
Yes. Denser packing — tighter cartons, removing excess packaging, compressing contents — increases density and can shift a shipment to a lower LTL class or reduce volumetric weight charges. Balance this against damage risk for fragile goods.