Volumetric Weight vs. Actual Weight in Air Freight: How Is It Calculated? Which Is More Expensive?

If you've ever shipped goods by air and wondered why you're sometimes charged for a weight greater than what the scale indicates, this article is for you. In air freight, airlines and cargo agents use the concept of "volumetric weight" (also called "dimensional weight") for billing purposes, especially when the goods are lightweight but take up a lot of space.
Below, we'll explain how it works, how to calculate it, and in which cases you'll pay more.

I. What Are Actual Weight and Volumetric Weight?

Actual Weight
This is the physical weight of the goods measured on a scale, usually in kilograms (kg).

Volumetric Weight
This is a weight calculated based on the volume of the goods, reflecting the space they occupy in the aircraft. It is based on the premise that an aircraft can be filled to capacity before reaching its weight limit.

II. Volumetric Weight Calculation Formula

The standard formula in air transport is:
Volumetric Weight (kg) = Length (cm) × Width (cm) × Height (cm) ÷ 6000

Explanation: The divisor 6000 is the standard volumetric conversion factor in aviation (some airlines use 5000 for certain services).

For example, a box measuring 90 cm × 90 cm × 80 cm:
Volume = 90 × 90 × 80 = 648,000 cm³
Volumetric weight = 648,000 ÷ 6000 = 108 kg

The standard formula for express courier shipping is:
Volumetric Weight (kg) = Length (cm) × Width (cm) × Height (cm) ÷ 5000

III. Which is Used for Billing?

Basic Rule:
The airline or freight forwarder will charge based on the greater of the Actual Weight and the Volumetric Weight. This value is called the "Chargeable Weight."

Formula:

Chargeable Weight = Maximum (Actual Weight, Volumetric Weight)

IV. Why Does This Rule Exist?

Airlines must optimize both maximum weight and limited cargo space.
If they only charged by actual weight, someone could ship 10 kg of feathers on a huge pallet, paying very little, but taking up space that could be used for denser, more cost-effective cargo.
Volumetric weight balances the cost between heavy and light bulky cargo.

V. Tips for Reducing Costs
- Compact packaging
- Reduce external dimensions whenever possible without damaging the goods.
- Choose tight-fitting boxes
- Avoid oversized boxes with excessive filler.
- Check the conversion factor
- Some carriers use 5000 instead of 6000 for certain routes or services (always verify).

VI. Frequently Asked Questions (FAQ)

Q1: Is 6000 always used for air freight?
No, some express services or certain agents use 5000. LCL (Less than Container Load) shipping typically uses 1000 or 500. Always check with your agent!

Q2: How can I tell if my shipment will be more expensive due to volume?
Calculate the volumetric weight using the formula and compare it to the actual weight. If the volumetric weight is higher, you will pay for that.

Q3: Are air freight rates charged per billable kg?
Yes, the rate (e.g., USD 8.50/kg) is applied to the billable weight, not the actual weight.

In air freight, the "volumetric weight" can mean a higher cost if you are shipping lightweight and bulky goods.

Remember: The final cost always depends on the greater of the actual weight and the volumetric weight!

Written by Yari