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In the field of international logistics, nothing is ever truly simple — especially when it comes to calculating shipping costs. Entrepreneurs often face an unexpected situation: a small box with lightweight goods suddenly “weighs” more than anticipated. Why is that? The answer lies in the concept of volumetric weight, which can sometimes be even more important than the actual weight. In this article, Dragon Logistics explains what volumetric weight is, how to calculate it, and why it’s critical for accurate planning of international shipments.
Actual vs. volumetric weight: the difference
Let’s start with the basics. Actual weight is the physical mass of the cargo, which can be measured on a regular scale. If a box weighs 5 kg, that’s its actual weight. However, in logistics, this isn’t always the key metric.
Volumetric (or dimensional) weight considers not only how much the cargo weighs but also how much space it takes up in the transport vehicle. For example, a light but bulky package takes up the same space in an aircraft as a dense heavy one. That’s why carriers use volumetric weight — a figure that reflects the economic value of the cargo’s space.
The formula for calculating volumetric weight is fairly simple, but it depends on the mode of transport. Most often, it’s calculated as follows:
- for air freight: (length × width × height in cm) ÷ 6000 = volumetric weight in kg;
- for sea or road freight: (length × width × height in cm) ÷ 5000 or 4000 — depending on the logistics provider.
For example, a box measuring 60×40×30 cm weighs only 5 kg. But its volumetric weight for air transport is (60×40×30) ÷ 6000 = 12 kg. And if that’s greater than the actual weight, the charge will be based on 12 kg.
Which weight does the carrier use?
A logistics company will always charge based on the greater of the two values—actual or volumetric weight. So, if your parcel weighs 5 kg but its volumetric weight is 12 kg, the chargeable weight will be 12 kg.
This rule allows carriers to use vehicle space efficiently and avoid losses from “shipping air” in containers or aircraft.
Why it’s important to know volumetric weight in advance
Incorrectly calculating shipping costs is one of the most common mistakes in international trade. Many entrepreneurs focus only on the actual weight, only to receive an invoice far higher than expected.
Knowing volumetric weight helps you:
- accurately calculate the cost price of goods;
- optimize packaging—less unused space means lower costs;
- compare rates from different carriers.
It also helps avoid unexpected charges when shipping from China, the USA, or the EU.
How to reduce volumetric weight
One of the best ways to save money is to optimize packaging. This means reducing empty space inside the box, using less bulky packing materials, and sometimes even changing the packaging shape.
In some cases, it’s worth using a 3PL (third-party logistics) provider, who can repackage your goods before shipping to reduce volume and cut costs.
Volumetric weight isn’t just an extra line item on your invoice — it’s the key to efficient logistics management, especially for international shipments. Understanding the difference between actual and volumetric weight, and knowing how to calculate them, is your safeguard against unexpected expenses and planning mistakes.
If you’re just starting with international freight, use online calculators or consult experienced logistics providers like Dragon Logistics, who can help you avoid extra costs and choose the most efficient delivery method.