Shipping costs can be confusing, especially when you realise that the weight you see on a scale isn’t always the weight used to calculate your shipping price. 

If you’re a business in South Africa looking to ship internationally, understanding volumetric weight vs actual weight can help you save money and optimise your logistics.

Key takeaways in this article:

• The difference between actual weight, volumetric weight, and chargeable weight.
• How to calculate both weights so you can avoid surprise costs.
• How to calculate shipping costs for your business. 
• Tips for reducing shipping costs, including how packaging affects volumetric weight.

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What Determines Your International Shipping Cost?

Couriers don’t just charge based on how much a package weighs, they also consider how much space it takes up. That’s where the concepts of actual weight, volumetric weight, and chargeable weight come in.

• Actual Weight: The physical weight of your package when placed on a scale.
• Volumetric Weight: A calculated weight based on the dimensions of the package (length, width, and height).‍
• Chargeable Weight: The higher of the two (actual vs volumetric) is your chargeable weight, and is used to determine the shipping cost.

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Understanding Volumetric Weight

Volumetric weight (also called dimensional weight) is crucial because large, lightweight packages take up more space in a courier’s vehicle. To calculate it, couriers use a standard formula:

Volumetric weight (kg) = (Length cm × Width cm × Height cm) / 5000

For example, if your package dimensions are 50cm x 40cm x 30cm:

Volumetric weight = (50 × 40 × 30) / 5000 = 12kg

If your package’s actual weight is only 8kg, the courier will charge you based on 12kg instead, because in this case the volumetric weight is higher than the actual weight.

💡Pro tip: Use TUNL’s Volumetric Weight Calculator below to make the maths quick and simple.

Real-World Example

Let’s say you’re shipping a lightweight but bulky pillow internationally. The actual weight is 2kg, but its dimensions (60cm x 50cm x 40cm) give a volumetric weight of 24kg. This means you’ll be charged for 24kg, not 2kg.

 💡Pro tip: Vacuum-sealing the pillow could significantly reduce the package size, lowering your shipping cost.

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How to Calculate Shipping Costs for Your Business

Follow these steps to accurately estimate your international shipping costs:

1. Weigh your package on a scale to get the actual weight.
2. Measure your package dimensions.
3. Use TUNL’s free Instant Rates Calculator to get an instant estimate for your shipment. 

💡Pro tip: Our Instant Rates Calculator calculates chargeable weight for you. If you would like to see how you are being charged, you can use our Volumetric Weight Calculator to compare actual and volumetric weight, and see if it’s possible to save money on shipping.

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Ways to Reduce Your Shipping Costs

If you’re shipping internationally, your costs can increase if you’re not optimising packaging. For example, if you package a pair of shoes in a box designed for a table, you will pay for the empty space in the box. 

Here’s how you can optimise: 

✅ Use smaller packaging: Reduce excess space to lower volumetric weight. Aim to get your volumetric weight as close as possible to your actual weight (think the opposite of how Takealot packages for local delivery). 

✅ Use poly mailers instead of boxes: Flexible packaging reduces unnecessary volume. Get more packaging tips here. 

✅ Bundle orders: Consolidating orders into one box can reduce wasted space.

✅ Work with a shipping partner like TUNL: Get discounted rates and smart shipping solutions to keep costs low.

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Final Thoughts

Understanding how your shipping costs are calculated can save your business thousands in unnecessary fees. By optimising packaging and using the right shipping tools, you can make international shipping more cost-effective.

Want to see how much you could be saving? Get an instant quote with TUNL and start optimising your shipping strategy today!

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