Rates Explained: Volume vs. Actual Weight in International Shipping
When it comes to international shipping, size really does matter 😅, especially when it comes to pricing. If you're a South African business looking to scale globally, knowing how shipping rates are calculated can save you serious 💰.
Here’s a quick, clear breakdown of how it all works, and how TUNL makes it easier.
Chargeable weight is the number that couriers use to calculate your shipping cost. It’s either:
the actual weight (what the parcel weighs on a scale), or
the volumetric weight (how much space it takes up),
...whichever is greater.
Why? Because a lightweight but bulky parcel still hogs space on the plane ✈️.
At TUNL, we calculate your chargeable weight automatically in our booking platform, so you don’t need a maths degree to ship globally 🎓.
Use this formula to work it out yourself (but we do it for you in the app when you book your shipment 😉):
Volumetric Weight (kg) = Length × Width × Height (cm) ÷ 5000
Let’s say your parcel is 50cm x 40cm x 30cm and weighs 6kg.
That’s: (50 × 40 × 30) ÷ 5000 = 12kg
Now imagine your actual weight is just 6kg - you’ll still be charged for 12kg, because that’s the higher number. 📦 > ⚖️
Here’s a simple way to think about it:
Whatever’s higher = your cost basis.
International couriers use half-kilogram (0.5kg) weight breaks. Here’s what that means:
📦 0.1kg to 0.5kg = charged as 0.5kg
📦 0.5001kg = charged as 1kg
📦 1.1kg = charged as 1.5kg
So if your parcel tips just over a break point, it gets rounded up. Every. Single. Time. 📈
We get it, no one wants to punch formulas into a calculator before sending a parcel 😵💫.
With TUNL, just pop in your parcel’s size and weight, and we’ll show you the chargeable weight instantly. That’s instant clarity, zero spreadsheets. 💡
Want to know how much you’ll pay?
🌐 Use our website for a quick quote (no login needed).
📍Need an exact rate to a specific address? Log in to our booking platform and get a precise quote in seconds.
Chargeable weights aren’t just for courier quotes, they’re essential for accurate pricing in your e-commerce store 🛒.
If you only use actual weight in your product listings, you risk:
Undercharging for shipping (💸 oops!)
Cart abandonment due to last-minute price jumps
Customer service headaches from mismatched delivery costs 😬
✅ Solution: Make sure your product weights reflect the chargeable weight, not just the scale weight. Most platforms like Shopify or WooCommerce let you input custom shipping weights, use this to your advantage.
👉 This helps you offer realistic, upfront pricing and keeps customers happy all the way to checkout.
Chargeable Weight = Higher of actual or volumetric weight
Volumetric Weight Formula = L x W x H / 5000
Couriers charge in 0.5kg weight breaks
TUNL auto-calculates it all, so you don’t have to
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Here’s a quick, clear breakdown of how it all works, and how TUNL makes it easier.
🚚 What Is Chargeable Weight?
Chargeable weight is the number that couriers use to calculate your shipping cost. It’s either:
the actual weight (what the parcel weighs on a scale), or
the volumetric weight (how much space it takes up),
...whichever is greater.
Why? Because a lightweight but bulky parcel still hogs space on the plane ✈️.
At TUNL, we calculate your chargeable weight automatically in our booking platform, so you don’t need a maths degree to ship globally 🎓.
📏 How to Calculate Volumetric Weight
Use this formula to work it out yourself (but we do it for you in the app when you book your shipment 😉):
Volumetric Weight (kg) = Length × Width × Height (cm) ÷ 5000
🔍 Real-World Example:
Let’s say your parcel is 50cm x 40cm x 30cm and weighs 6kg.
That’s: (50 × 40 × 30) ÷ 5000 = 12kg
Now imagine your actual weight is just 6kg - you’ll still be charged for 12kg, because that’s the higher number. 📦 > ⚖️
⚖️ Actual vs Volumetric: Which One Counts?
Here’s a simple way to think about it:
| Parcel Type | Weight | Volume | Chargeable Weight |
|---|---|---|---|
| Small & heavy ⚒️ | 10kg | 6kg | 10kg |
| Big & light 🎈 | 4kg | 8kg | 8kg |
| Perfect cube 🧊 | 12kg | 12kg | 12kg |
Whatever’s higher = your cost basis.
🧮 Weight Breaks & Courier Rates
International couriers use half-kilogram (0.5kg) weight breaks. Here’s what that means:
📦 0.1kg to 0.5kg = charged as 0.5kg
📦 0.5001kg = charged as 1kg
📦 1.1kg = charged as 1.5kg
So if your parcel tips just over a break point, it gets rounded up. Every. Single. Time. 📈
🔧 TUNL’s Built-In Chargeable Weight Tool
We get it, no one wants to punch formulas into a calculator before sending a parcel 😵💫.
With TUNL, just pop in your parcel’s size and weight, and we’ll show you the chargeable weight instantly. That’s instant clarity, zero spreadsheets. 💡
💻 Get a Quick or Exact Shipping Quote
Want to know how much you’ll pay?
🌐 Use our website for a quick quote (no login needed).
📍Need an exact rate to a specific address? Log in to our booking platform and get a precise quote in seconds.
🧠 Pro Tip: Sync Chargeable Weights to Your Online Store
Chargeable weights aren’t just for courier quotes, they’re essential for accurate pricing in your e-commerce store 🛒.
If you only use actual weight in your product listings, you risk:
Undercharging for shipping (💸 oops!)
Cart abandonment due to last-minute price jumps
Customer service headaches from mismatched delivery costs 😬
✅ Solution: Make sure your product weights reflect the chargeable weight, not just the scale weight. Most platforms like Shopify or WooCommerce let you input custom shipping weights, use this to your advantage.
👉 This helps you offer realistic, upfront pricing and keeps customers happy all the way to checkout.
✅ TL;DR – Your Shipping Cheat Sheet
Chargeable Weight = Higher of actual or volumetric weight
Volumetric Weight Formula = L x W x H / 5000
Couriers charge in 0.5kg weight breaks
TUNL auto-calculates it all, so you don’t have to
Keywords: chargeable weight calculation | volumetric vs actual weight | international shipping costs from South Africa | how to calculate shipping weight | shipping rates for South African SMEs | affordable international shipping from South Africa | how to reduce shipping costs for SMEs | bulk shipping cost reduction strategies | landed cost calculator for global shipping | best couriers for international shipping from South Africa | shipping weight guide for e-commerce businesses | WooCommerce and Shopify shipping weight integration | cross-border shipping pricing tips
Updated on: 20/06/2025
Thank you!