When requesting an international freight quotation, many businesses often ask:

"My shipment only weighs 15 kg, so why is the shipping carrier charging me for 24 kg?"

The answer lies in DIM (Dimensional Weight)—one of the most important factors that determines shipping costs in international logistics.

Without a clear understanding of how DIM is calculated, businesses may face unexpected shipping expenses or use packaging that is far from cost-efficient.

In this article, SongWin International Logistics explains what DIM is, how dimensional weight is calculated, and practical tips to help optimize your transportation costs.

What Is DIM in Import and Export?

DIM (Dimensional Weight), also known as Volumetric Weight, is the weight calculated based on a shipment's dimensions rather than its actual physical weight.

Simply put, shipping carriers consider not only how heavy a package is but also how much space it occupies in an aircraft, truck, or shipping container.

This pricing method is widely adopted by airlines, express couriers such as DHL, FedEx, UPS, and many international logistics providers.

Why Do Carriers Charge Based on DIM?

In practice, two packages may each weigh 10 kg, yet their shipping charges can differ significantly.

For example:

• A box of metal components weighs 10 kg but is compact in size.
• A carton of stuffed toys also weighs 10 kg but occupies several times more cargo space.

For transportation companies, cargo space is a limited resource. If freight charges were calculated solely based on actual weight, lightweight but bulky shipments would reduce the efficiency of cargo capacity utilization.

Therefore, Dimensional Weight is used to ensure shipping costs accurately reflect the amount of space occupied by the cargo.

What Is Chargeable Weight?

In the logistics industry, shipping charges are not calculated using only one weight measurement. Instead, carriers compare:

• Gross Weight (GW): The actual weight after packaging.
• Dimensional Weight (DIM): The weight converted from the package dimensions.

Whichever value is greater becomes the Chargeable Weight (CW) used for freight calculation.

This principle applies to most air freight and international express shipments.

DIM Calculation Formula

The formula for calculating Dimensional Weight is straightforward:

DIM (kg) = (Length × Width × Height) ÷ Conversion Factor

Where:

• Length (cm)
• Width (cm)
• Height (cm)

The conversion factor varies depending on the transportation method.

Note: Each carrier may apply different conversion factors depending on the shipping route or service. Businesses should always verify the applicable factor before planning a shipment.

Practical Example

SongWin receives a quotation request with the following shipment details:

• Dimensions: 60 × 50 × 40 cm
• Gross Weight: 15 kg
• Shipping Method: International Express

Calculate DIM:

DIM = (60 × 50 × 40) ÷ 5,000 = 24 kg

Comparison:

• Gross Weight: 15 kg
• DIM: 24 kg

Since the Dimensional Weight is greater, the Chargeable Weight will be 24 kg.

This situation is common when shipping:

• Product samples
• Promotional materials
• Garments
• Lightweight but bulky products

Products Commonly Charged by Dimensional Weight

Based on SongWin's extensive logistics experience, the following products frequently incur dimensional weight charges:

• Furniture
• Knock-down wooden furniture
• Bedding and mattresses
• Garments
• Stuffed toys
• Plastic products
• Decorative items
• Packaging materials
• Cartons
• Advertising displays

For these products, optimizing packaging dimensions can significantly reduce transportation costs.

Practical Tips to Reduce DIM from a Freight Forwarder's Perspective

As a freight forwarder working closely with shipping lines, airlines, and international courier companies, SongWin recommends the following best practices before shipping your cargo.

Choose the Right Packaging Size

Many businesses use oversized cartons for additional protection. However, larger packaging increases Dimensional Weight and consequently raises shipping costs.

Minimize Empty Space Inside the Carton

If there is excessive empty space inside the package, use suitable cushioning materials instead of selecting a larger carton than necessary.

Vacuum-Pack Soft Goods

For garments, bedding, stuffed toys, and textile products, vacuum packaging can significantly reduce package height and lower dimensional weight.

Design Packaging Efficiently from the Beginning

Optimizing package dimensions during product design and manufacturing is much more effective than attempting to reduce package size after production is complete.

Consult Your Freight Forwarder Before Packing

This is a common practice among experienced exporters.

Simply providing the estimated package dimensions allows your freight forwarder to:

• Calculate Dimensional Weight
• Estimate Chargeable Weight
• Recommend the most cost-effective packaging solution before shipment

This helps businesses control logistics budgets and avoid unexpected shipping costs.

SongWin Helps Businesses Optimize Shipping Costs

At SongWin International Logistics, we do more than provide international transportation services—we support our customers from the very beginning of the shipping process.

Our logistics specialists can assist with:

• Calculating Dimensional Weight and Chargeable Weight before providing quotations
• Advising on the most suitable packaging for different cargo types
• Selecting the optimal transportation method among ocean freight, air freight, and express courier services
• Minimizing additional charges caused by oversized packages

With extensive experience handling a wide range of import and export commodities, SongWin is committed to delivering logistics solutions that are safe, cost-effective, and on schedule, helping businesses improve supply chain efficiency.

Conclusion

Dimensional Weight is one of the most significant factors affecting shipping costs, yet it is often overlooked during shipment preparation.

Understanding how to calculate DIM enables businesses to make better packaging decisions, choose the most suitable transportation method, and maintain greater control over logistics expenses.

If your company needs professional advice on Dimensional Weight, international freight quotations, customs clearance, or integrated logistics solutions, contact SongWin International Logistics today. We are committed to providing the most efficient shipping solutions for every shipment.

SONGWIN INTERNATIONAL LOGISTICS VIETNAM CO., LTD.

📍 Address: 344 Nguyen Trong Tuyen Street, Tan Son Hoa Ward, Ho Chi Minh City, Vietnam

📞 24/7 Hotline: +84 83 681 3969 | +84 373 262 105

📧 Email: Sales2@songwinlog.com

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