Why Is There a Shipping Rate Difference Between TUNL and My Store? 📦💸
So, you’ve just booked a shipment on TUNL, but the rate looks different from what your customer saw at checkout? 🤔 Don’t stress - it’s not a glitch in the matrix. Here’s what’s likely going on (and how to fix it for good).
🧭 TL;DR: To keep your shipping costs accurate and consistent, make sure your product weights are set up correctly and that you understand how chargeable weight works.
Setting product weights in your eCommerce store isn’t just a box to tick - it’s essential for:
Showing accurate shipping rates at checkout
Avoiding undercharging (which eats into your margins) 😬
Preventing overcharging (which can lead to cart abandonment) 🛒
Let’s make sure your store’s weights reflect reality.
Couriers don’t just bill based on what the scale says. They use something called chargeable weight, which is:
The higher of:
Actual weight (kg) ⚖️
Volumetric weight (based on size) 📐
Let’s say your parcel looks like this:
Dimensions: 50cm x 30cm x 10cm
Actual Weight: 1kg
Now let’s do the math 👇
Volumetric Weight = (50 × 30 × 10) ÷ 5000 = 3kg
Actual Weight = 1kg
✅ Chargeable Weight = 3kg
(Because volumetric is higher than actual)
📝 Always remember: couriers will charge for whichever is bigger, mass or volume. And this is where product dimensions can really sneak up on your costs.
Examples:
A feather-light pillow 🛏️? Probably gets charged based on volume.
A dense jar of jam 🍯? Charged on actual weight.
So if your product is big but light or small but heavy, your customer’s shipping rate might not reflect the final TUNL rate unless your setup accounts for this.
Are your customers buying:
One item at a time?
Or do they bundle up two or three goodies per order?
The more items in a parcel, the more likely you’ll move into a different pricing bracket. Couriers typically charge in 0.5kg increments, so even small differences can affect your final cost.
💡 Pro tip: If you can fit two items in the same box, that could save you (and your customer) money. But only if your product weights reflect this accurately.
If your parcels are playing Tetris badly, full of dead space and awkward shapes, you might be paying extra for air. That’s where multi-piece shipments come in handy. Splitting items into separate parcels can help you dodge high volumetric weight and save on costs.
👉 Need help? Follow our How to Book a Multi-piece Shipment guide.
Get hands-on! We recommend physically weighing and measuring your products. Here’s how:
Start with one product:
Weigh & measure unpacked
Weigh & measure packed (ready to ship)
Try a bundle:
Pack two items together
Weigh the packed bundle
🎯 Once you’ve got your numbers, update your product listings in Shopify or WooCommerce.
Don’t forget: If you’re adding duties & taxes at checkout, you’ll also need to add the **HS Code** to each product.
One last thing - if your customer lives in an outlying area, extra courier fees might apply. These won’t show up in your store unless you’re using TUNL’s Shopify Live Rates Integration.
📌 If you're not using Live Rates, the charge may appear only when booking via your TUNL profile.
Which integration is best for you?
Shopify Basic Rates Integration
Shopify Live Rates Integration
WooCommerce Rates Integration
Email us at support@tunl.to and we’ll help you sort it out, no spreadsheets required 😉
🧭 TL;DR: To keep your shipping costs accurate and consistent, make sure your product weights are set up correctly and that you understand how chargeable weight works.
1. It All Starts With Product Weights ⚖️
Setting product weights in your eCommerce store isn’t just a box to tick - it’s essential for:
Showing accurate shipping rates at checkout
Avoiding undercharging (which eats into your margins) 😬
Preventing overcharging (which can lead to cart abandonment) 🛒
Let’s make sure your store’s weights reflect reality.
2. Chargeable Weight: The Crux of Your Shipping Costs 📏📦
Couriers don’t just bill based on what the scale says. They use something called chargeable weight, which is:
The higher of:
Actual weight (kg) ⚖️
Volumetric weight (based on size) 📐
🧠 Example Time!
Let’s say your parcel looks like this:
Dimensions: 50cm x 30cm x 10cm
Actual Weight: 1kg
Now let’s do the math 👇
Volumetric Weight = (50 × 30 × 10) ÷ 5000 = 3kg
Actual Weight = 1kg
✅ Chargeable Weight = 3kg
(Because volumetric is higher than actual)
📝 Always remember: couriers will charge for whichever is bigger, mass or volume. And this is where product dimensions can really sneak up on your costs.
Examples:
A feather-light pillow 🛏️? Probably gets charged based on volume.
A dense jar of jam 🍯? Charged on actual weight.
So if your product is big but light or small but heavy, your customer’s shipping rate might not reflect the final TUNL rate unless your setup accounts for this.
3. Think About Cart Size 🛍️
Are your customers buying:
One item at a time?
Or do they bundle up two or three goodies per order?
The more items in a parcel, the more likely you’ll move into a different pricing bracket. Couriers typically charge in 0.5kg increments, so even small differences can affect your final cost.
💡 Pro tip: If you can fit two items in the same box, that could save you (and your customer) money. But only if your product weights reflect this accurately.
4. Multi-Piece Shipments for Weird Shapes 🧩📦
If your parcels are playing Tetris badly, full of dead space and awkward shapes, you might be paying extra for air. That’s where multi-piece shipments come in handy. Splitting items into separate parcels can help you dodge high volumetric weight and save on costs.
👉 Need help? Follow our How to Book a Multi-piece Shipment guide.
5. How to Weigh Your Products Properly 🪙📏
Get hands-on! We recommend physically weighing and measuring your products. Here’s how:
Start with one product:
Weigh & measure unpacked
Weigh & measure packed (ready to ship)
Try a bundle:
Pack two items together
Weigh the packed bundle
🎯 Once you’ve got your numbers, update your product listings in Shopify or WooCommerce.
Don’t forget: If you’re adding duties & taxes at checkout, you’ll also need to add the **HS Code** to each product.
6. Outlying Area Charges 🏞️
One last thing - if your customer lives in an outlying area, extra courier fees might apply. These won’t show up in your store unless you’re using TUNL’s Shopify Live Rates Integration.
📌 If you're not using Live Rates, the charge may appear only when booking via your TUNL profile.
**Related Articles 🧠**
Which integration is best for you?
Shopify Basic Rates Integration
Shopify Live Rates Integration
WooCommerce Rates Integration
Still stuck? We’ve got your back 💬
Email us at support@tunl.to and we’ll help you sort it out, no spreadsheets required 😉
Updated on: 20/06/2025
Thank you!