Introduction to Weights and Measures in Air Freight
In air cargo transport, understanding the different types of weights and measures is fundamental. These concepts determine not only the cost of transport but also how goods are handled, loaded, and transported. A precise knowledge of these concepts allows shippers to optimize their shipments and control their logistics costs.
The four main types of weight used in air freight are:
- The gross weight (Gross Weight, abbreviated G.W.)
- The net weight (Net Weight, abbreviated N.W.)
- The volumetric weight (Volume Weight, abbreviated V.W.)
- The chargeable weight (Chargeable Weight, abbreviated C.W.)
Each of these weights has a specific meaning and use in the air logistics chain. Understanding them is essential for all professionals in the sector, from shippers to freight forwarders, airlines, and handling agents.
Gross Weight (Gross Weight)
Definition of Gross Weight
The gross weight represents the total weight of a shipment, including both the goods themselves and all packaging materials (boxes, pallets, plastic wrap, dunnage materials, etc.). It is the actual weight that will be physically transported by the aircraft.
Importance of Gross Weight
Gross weight is crucial for several reasons:
- Air safety: Aircraft have strict weight limits that cannot be exceeded to ensure flight safety.
- Loading planning: Loading managers must know the exact weight of each shipment to properly balance the aircraft.
- Billing: In some cases, gross weight may be used as the billing basis if it is higher than the volumetric weight.
- Regulatory compliance: Many regulations require the accurate declaration of gross weight.
Measurement of Gross Weight
Gross weight is generally measured in kilograms (kg) or pounds (lb) depending on the region. The standard conversion is: 1 kg = 2.20462 lb.
The measurement of gross weight is done using calibrated and certified scales. In air freight, this operation is often performed at several stages:
- At the shipper's location, during shipment preparation
- At the freight forwarder's location, during consolidation
- At the airport, during acceptance of the freight by the airline (official weighing)
Good to Know
Weight discrepancies between different weighings can lead to billing adjustments. Typically, the weighing performed by the airline is considered final for billing purposes.
Net Weight (Net Weight)
Definition of Net Weight
The net weight represents only the weight of the goods themselves, excluding packaging materials. It is the "pure" weight of the goods being transported.
Importance of Net Weight
Net weight is important for several reasons:
- Customs declarations: Many customs authorities require the declaration of net weight for the calculation of duties and taxes.
- Business analysis: Net weight allows for the comparison of value per unit weight of goods.
- Statistics: International trade statistics are often based on net weight.
- Quality control: In some industries, net weight is used to verify product compliance.
Calculation of Net Weight
Net weight can be calculated in two ways:
- Direct method: Weigh the goods directly before packaging.
- Indirect method: Subtract the weight of the packaging from the total gross weight.
Formula: Net Weight = Gross Weight - Packaging Weight
Relationship with Gross Weight
The difference between gross weight and net weight can vary significantly depending on the type of goods and packaging. For some heavy industrial products, this difference may be minimal (5-10%), while for light products requiring substantial protective packaging, it can represent up to 50% or more of the gross weight.
Practical Example
A shipment of electronic components weighs 100 kg gross. The components themselves weigh 75 kg, while the packaging (boxes, foam protection, pallet) weighs 25 kg. The net weight is therefore 75 kg.
Volumetric Weight (Volume Weight)
Definition of Volumetric Weight
The volumetric weight, or dimensional weight, is a theoretical weight used to reflect the space occupied by light but bulky cargo in an aircraft. It is calculated from the volume of the shipment and a standard conversion factor defined by IATA.
Why Use Volumetric Weight?
In air freight, available space is as valuable as the weight transported. A light but bulky item can cost more to transport than a small, dense package. Volumetric weight thus adjusts the pricing according to the space used.
Calculation Formula
Volumetric Weight (kg) = (Length × Width × Height in cm) ÷ 6000
This calculation uses a standard conversion factor of 167 kg/m³ (1,000,000 ÷ 167 ≈ 6000).
Example
- Dimensions: 120 cm × 80 cm × 60 cm
- Gross Weight: 40 kg
- Volumetric Weight = (120 × 80 × 60) ÷ 6000 = 96 kg
In this example, even though the package weighs 40 kg, it will be billed based on 96 kg due to its volume.
Good to Know
Some carriers use different factors (e.g., 200 kg/m³ for express), so it is always recommended to verify with the provider.
Chargeable Weight (Chargeable Weight)
Definition of Chargeable Weight
The chargeable weight is the weight used by airlines to calculate the cost of transport. It corresponds to the higher of the gross weight and the volumetric weight of a shipment.
Determination of Chargeable Weight
Once the gross weight and volumetric weight are known, the chargeable weight is determined by the following rule:
Chargeable Weight = Maximum (Gross Weight, Volumetric Weight)
In other words:
- If the gross weight is higher than the volumetric weight, the chargeable weight will be equal to the gross weight.
- If the volumetric weight is higher than the gross weight, the chargeable weight will be equal to the volumetric weight.
Examples of Chargeable Weight Calculation
Example 1: Dense Package (Gross Weight > Volumetric Weight)
A package of metal parts with the following characteristics:
- Dimensions: 50 cm × 40 cm × 30 cm
- Gross Weight: 45 kg
Calculation:
- Volume = 50 × 40 × 30 ÷ 1,000,000 = 0.06 m³
- Volumetric Weight = 0.06 × 167 = 10.02 kg
- Chargeable Weight = max(45, 10.02) = 45 kg
In this example, the gross weight (45 kg) is higher than the volumetric weight (10.02 kg), so the chargeable weight is 45 kg.
Example 2: Bulky Package (Volumetric Weight > Gross Weight)
A package of clothing with the following characteristics:
- Dimensions: 100 cm × 80 cm × 60 cm
- Gross Weight: 30 kg
Calculation:
- Volume = 100 × 80 × 60 ÷ 1,000,000 = 0.48 m³
- Volumetric Weight = 0.48 × 167 = 80.16 kg
- Chargeable Weight = max(30, 80.16) = 80.16 kg
In this example, the volumetric weight (80.16 kg) is higher than the gross weight (30 kg), so the chargeable weight is 80.16 kg.
Regional Conversion Factors
Although the standard IATA factor is 167 kg/m³, some airlines or routes may apply different factors:
- International air transport (IATA): 167 kg/m³
- Domestic air transport (some countries): 166 kg/m³
- Express transport (some integrators): up to 200 kg/m³
It is always recommended to verify the exact factor applied by your carrier.
Practical Implications for Shippers
Optimization of Shipments
Understanding the concepts of gross, net, and chargeable weight allows shippers to optimize their shipments and reduce logistics costs. Here are some optimization strategies:
For Shipments Where Gross Weight is Determinant:
- Reduce packaging weight: Use lighter packaging materials while maintaining adequate protection.
- Optimize density: Maximize the quantity of products per unit of volume.
- Eliminate empty spaces: Use custom packaging to avoid unnecessary spaces.
For Shipments Where Volumetric Weight is Determinant:
- Reduce dimensions: Use packaging that fits the size of the products.
- Compact products: If possible, fold, stack, or nest products to reduce their volume.
- Reconsider the mode of transport: For very bulky but light shipments, sea transport may be more economical.
Comparison Between Gross Weight, Net Weight, and Chargeable Weight
| Characteristic |
Gross Weight |
Net Weight |
Chargeable Weight |
| Definition |
Total weight of the shipment (goods + packaging) |
Weight of the goods without packaging |
Maximum between gross weight and volumetric weight |
| Main Use |
Billing, safety, loading planning |
Customs declarations, business analysis |
Air transport billing |
| Calculation |
Direct weighing of the complete shipment |
Gross Weight - Packaging Weight |
Max(Gross Weight, Volume × Conversion Factor) |
| Importance |
Flight safety, regulatory compliance |
Calculation of duties and taxes, statistics |
Optimization of transport costs |
Practical Tips for Air Freight Professionals
Weight Verification
Ensure that all weights (gross, net, chargeable) are correctly calculated and verified before shipment. An error can result in additional costs or delays.
Packaging Optimization
Use lightweight but robust packaging materials to minimize gross weight without compromising the safety of the goods.
Use of Digital Tools
Adopt freight management software to automate weight calculations and optimize loading processes.
Continuous Training
Stay informed about regulations and best practices regarding weights and measures in air freight. Continuous training is essential to adapt to changes in the sector.
Weight Discrepancy Management
Implement procedures to manage weight discrepancies between different weighings. Clear communication with carriers can help resolve these discrepancies quickly.
Conclusion
Mastery of weight and measurement concepts is essential for optimizing air freight operations. By understanding the differences between gross, net, and chargeable weight, and applying best practices, professionals can improve efficiency and reduce the costs of their shipments.
