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What Size of Mailing Boxes will fit into Australia Post Prepaid Satchels? - Awesome Pack’s Mailing Box Dimensions Guide

Auspost Prepaid Satchels is a common way to mail your goods for a small business but sometimes you want to put your product in a cardboard box before you slide it in the satchel for protection & presentation. This Mailing Box Size Guide will help you answer common questions relating to what size mailing boxes will fit into certain Australia Post Satchels or any other plain satchel of a certain size.


mailing boxes white and brown


In order to understand what size Cardboard Box will fit into a certain satchel size you firstly need to understand the following concept:

Boxes are 3 Dimensional with Length x Width x Height whereas Satchel sizes are 2 Dimensional with only Length x Width.

So when considering what size courier bag/satchel to buy for your cardboard box you need to understand that the length, width and height will all need to be considered. Please don’t fall into the trap of buying a satchel size that has a length and width similar to a mailing box and thinking it will fit. This way of thinking omit the consideration of height of the box and therefore will often not fit.

As a general rule, in order for a mailing box to fit inside a mailing satchel, the satchel length and width need to be substantially bigger than the length and width of the mailing box. How much bigger? Well that depends on the height of the box.

The table below will give you an approximation of what mailing box will fit into the Australia Post prepaid Satchel:


Parcel Post/Express Post

[Max weight 5kg]

Bag Dimension

[Length x Width]

Fits into:

Mailing Box Dimension

[Length x Width x Height]

Small Satchel

355 x 225mm


Medium Satchel

390 x 270 mm


Large Satchel

415 x 315 mm


Extra Large Satchel

510 x 440mm



We know your mailing box may be a unique size with different length, width and height, so the best way to know if to purchase one of our Sample packs below which gives you one of every size for you to try at the comfort of your own home, office or warehouse.


We have 3 sample packs below:

White Plastic Courier Bags [All 9 Sizes]

Black Plastic Courier Bags [All 6 Sizes]

Compostable Courier Bags [All 4 Sizes]


Another reason why buying a Sample pack is useful is when you have new products or new packaging you immediately have all the courier bags sizes on hand to try it on which will save you time and money. It is a must have for the growing eCommerce business owner.


Once you know the size you need and you cannot find a quantity large enough on our website then please call us on 1300 816 800 or email us at sales@awesomepack.com.au and we can give you a competitive quote that will guarantee the best price in the market. Please note for a custom quote we require a minimum of 2000 bags per size.


I hope we at Awesome Pack have helped you in some way by reading this article and we wish you the best of luck in the ever changing eCommerce industry.


Always bringing you value to your eCommerce journey,


Bill Li


Awesome Pack

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