For WooCommerce stores shipping domestically across Australia, predictable shipping costs are one of the biggest operational advantages you can build into your store. Australia Post flat rate satchels, available through MyPost Business, offer exactly that — a fixed postage price based on satchel size rather than destination or weight, as long as your parcel stays within the limit.
This article explains how flat rate satchels work, what sizes are available, and how to configure them in WooCommerce to display accurate rates at checkout.
On This Page
- What Are Australia Post Flat Rate Satchels?
- Australia Post MyPost Business Flat Rate Satchel Sizes
- Why WooCommerce Stores Benefit from Flat Rate Satchels
- How to Configure Flat Rate Satchels in WooCommerce via MyPost Business
- Real-World Use Case: Flat Rate Satchels for an Australian WooCommerce Store
- Conclusion
- FAQs
What Are Australia Post Flat Rate Satchels?
Australia Post flat rate satchels are prepaid mailing satchels that let you ship orders for a fixed postage price, regardless of where in Australia the parcel is going, as long as the contents fit inside the satchel and stay within the 5 kg weight limit. Instead of calculating postage based on destination and weight separately, the cost is determined purely by the satchel size you use.
This makes them particularly useful for WooCommerce stores selling products that vary in weight but fit within standard satchel dimensions — clothing, accessories, small electronics, books, and similar goods. The pricing stays predictable, the checkout experience is cleaner, and your fulfillment workflow becomes easier to manage at scale.
Australia Post MyPost Business Flat Rate Satchel Sizes
Australia Post offers flat-rate satchels in four standard sizes under the MyPost Business program. Each size has fixed external dimensions and a maximum weight allowance of 5 kg for flat rate postage eligibility:
- Small flat-rate satchels measure approximately 355 x 225mm, and are well-suited for slim, lightweight items like documents, folded clothing, or accessories.
- Medium flat-rate satchels measure approximately 390 x 270mm, and work well for slightly bulkier items or multi-item orders that still sit comfortably within the satchel dimensions.
- Large flat-rate satchels measure approximately 415 x 315mm and are designed to hold items weighing up to 5 kg. They are a practical choice for mid-sized products like folded garments, footwear, or packaged goods.
- Extra-large flat-rate satchels measure 510 x 440mm. These are the largest flat-rate satchel options and suit bulkier or multi-item orders where the contents spread out rather than stack.
All four satchels follow the same rule: if you are sending 5 kg or under in Australia using flat rate packaging, postage is based on the size of the package rather than the weight and destination. If a parcel exceeds 5 kg or is headed overseas, standard weight and destination-based pricing apply instead.
In addition to satchels, Australia Post also offers flat-rate padded mailers for smaller, more delicate items. Extra small flat rate padded mailers measure 280 x 215mm and are a good option for jewellery, cosmetics, or other compact products that benefit from extra padding.
Why WooCommerce Stores Benefit from Flat Rate Satchels
Flat rate satchels remove the complexity of weight and destination-based postage calculations for eligible domestic orders. For WooCommerce store owners, this means:
- Predictable shipping costs that don’t change based on the customer’s location within Australia.
- Cleaner checkout experience for customers, who see a straightforward postage cost tied to the satchel size rather than variable rates.
- Simpler fulfillment decisions, since staff can select the correct satchel based on product size rather than calculating postage case by case.
- Better margin control, especially as order volume grows, because postage costs remain consistent and predictable across all domestic orders using satchels.
How to Configure Flat Rate Satchels in WooCommerce via MyPost Business
To use Australia Post flat rate satchels in WooCommerce, you need to install and activate the PH Australia Post MyPost Business Shipping Plugin for WooCommerce. The plugin connects your store directly to Australia Post MyPost Business and calculates shipping rates based on how you pack your products.
To configure the plugin in your WooCommerce store, refer to this guide: Setting Up Australia Post Shipping Plugin for WooCommerce .
After you install the plugin and configure your MyPost Business account credentials, you can manage packaging directly from the plugin settings. The plugin offers several packing options based on how your store operates:
- Pack products individually
- Pack products based on weight
- Use Australia Post MyPost Business boxes or custom boxes
For stores using official Australia Post flat rate satchels, the plugin lets you select the predefined MyPost Business satchels directly within the packaging settings.
The plugin then automatically selects the best-fit satchel for each order based on the product’s dimensions entered in WooCommerce, and fetches the correct flat rate postage accordingly.
If you use your own custom packaging alongside or instead of Australia Post satchels, you can also define custom box dimensions within the plugin. The plugin calculates the best fit and requests accurate MyPost Business rates based on those dimensions.
This plugin also lets you generate and print labels from the WooCommerce dashboard itself. Read this guide to learn more: Print Australia Post MyPost Business Shipping Label in WooCommerce.
For accurate rate calculation across all packing methods, make sure each product in your WooCommerce store has its weight and dimensions correctly entered. Without this data, the plugin cannot determine the right satchel size or calculate cubic weight accurately.
Real-World Use Case: Flat Rate Satchels for an Australian WooCommerce Store
An Australian WooCommerce store selling clothing and lifestyle accessories was processing around 60 to 100 orders per week. Most products — folded garments, scarves, small homewares — fit comfortably within medium or large Australia Post satchels. Despite this, their shipping setup was creating recurring issues.
The Challenges
- Shipping rates at checkout were inconsistent because product dimensions were not properly configured in WooCommerce.
- Staff were selecting satchel sizes manually for each order, leading to occasional oversizing and unnecessary cost increases.
- The postage cost shown at checkout sometimes differed from what was charged via the MyPost Business portal.
- Fulfillment time was longer than it needed to be due to manual packaging decisions.
How the Plugin Helped
After integrating the PH Australia Post MyPost Business Shipping Plugin for WooCommerce, the store configured official flat rate satchel sizes within the plugin settings. Once live:
- The plugin automatically matched each order to the correct satchel size based on product dimensions.
- Live flat rate postage appeared accurately at checkout, matching what was charged when the label was generated.
- Manual packaging decisions were eliminated, reducing fulfillment time on busy dispatch days.
- Shipping costs became consistent and predictable, making margin planning far more straightforward.
After these changes, the store improved checkout accuracy, reduced shipping costs, and sped up fulfillment. Overall, the team saved time and worked more efficiently.
Conclusion
Australia Post flat-rate satchels are one of the most practical packaging options for WooCommerce stores shipping domestically. The PH Australia Post MyPost Business Shipping Plugin for WooCommerce lets you configure flat rate satchels in minutes. It ensures accurate checkout rates and a smoother fulfillment process.
If you need help setting up flat rate satchels in your WooCommerce store, reach out to PluginHive Support.
FAQs
Q. Do flat-rate satchels work for all Australian destinations via MyPost Business?
Yes. Australia Post flat rate satchels cover delivery to all Australian addresses. As long as the parcel fits within the satchel and weighs 5 kg or under, the postage cost is the same regardless of destination.
Q. Can I combine flat rate satchels with other shipping options at checkout in WooCommerce?
Yes. The WooCommerce Table Rate Shipping Pro Plugin, lets you offer flat rate satchel postage alongside other shipping options. You can also combine it with weight-based rates or free shipping above a certain cart value to give customers more flexibility at checkout.
Q. Can multi-vendor WooCommerce stores use flat rate satchels with MyPost Business?
Yes. The WooCommerce Multi-Vendor Shipping Addon, allows each vendor to configure their own packaging rules and satchel sizes, ensuring accurate flat rate postage for each order.
Q. What happens if a parcel exceeds 5 kg in a flat rate satchel?
If your parcel weighs more than 5 kg, it does not qualify for flat rate postage. Australia Post calculates postage using standard MyPost Business rates. It uses the greater of actual or cubic weight along with the destination.
Q. Can I manage Australia Post tracking for flat rate satchel orders in WooCommerce?
Yes. Basic tracking is supported within the plugin. For advanced tracking updates and automated customer notifications, you can integrate with the WooCommerce Shipment Tracking Pro Plugin.
