Mailing Boxes Guide

If you’re shipping products in Australia, your packaging is doing more than just getting something from A to B.

It’s protecting your product, representing your brand, and whether you like it or not, it’s part of your customer experience.

HeapsGood mailing boxes are built for exactly that. Durable, clean, and made from up to 99.9% recycled materials, they’re designed to work with Australia Post, reduce waste, and still look the part when they land on someone’s doorstep.

No overcomplicated systems. No plastic-heavy nonsense. Just boxes that actually make sense for modern ecommerce.

Browse the full range of Mailing Boxes

Australia Post Approved Mailer Box Sizes and Specs

AusPost pricing is heavily influenced by size and weight, especially cubic weight.

If your box is oversized, you’re paying more than you need to.

Here’s a simple breakdown of common mailer box sizes and how they align:

Size	Dimensions (mm)	Best Use	AusPost Fit
XS	150 x 100 x 50	Small accessories	Small parcel
S	175 x 130 x 65	Cosmetics, small goods	Small parcel
M	220 x 160 x 77	Apparel, books	Standard parcel
L	310 x 225 x 102	Multi-item orders	Medium parcel
XL	400 x 200 x 180	Bulk items	Larger parcels

Key things to keep in mind:

• Keep packaging tight to avoid cubic weight increases

• Stay under key size thresholds where possible

• Match box size to your most common order

HeapsGood boxes are designed with this in mind, so you’re not guessing or overpaying.

HeapsGood Mailer Boxes: Product Range and Features

The range is simple on purpose. No 50 variations you don’t need. The core features across all boxes:

• Made from up to 99.9% recycled cardboard

• Fully recyclable and compostable

• Single-wall B-flute construction

• Lightweight but durable

• Clean kraft finish for branding

Available sizes

Size	Dimensions (mm)	Volume	Weight Per Box	Best Use
XS	150 x 100 x 50	0.75L	50g	Best for small items and samples
S	175 x 130 x 65	1.47L	64g	Great for compact ecommerce orders
M	220 x 160 x 77	2.7L	119.2g	The go-to for apparel and general goods
L	310 x 225 x 102	7.1L	128g	Perfect for multi-product orders
XL	400 x 200 x 180	14L	300g	The GOAT for bulkier shipments

Each size is designed to balance strength and cost. No unnecessary thickness, no wasted space.

What Makes These Boxes Sustainable?

Traditional packaging is still heavily reliant on single-use plastic. It’s cheap upfront, but it comes with long-term environmental costs.

Most plastic packaging gets used once, then sits in landfill or the environment for decades. HeapsGood was built to challenge that by replacing outdated materials with recyclable and compostable alternatives wherever possible. Our mailer boxes solve two problems at once:

• Reduce environmental impact

• Maintain or improve product protection

HeapsGood boxes focus on:

Recycled content
Up to 99.9% post-consumer recycled cardboard

Plastic-free design
No hidden plastic layers or coatings

Compostable and recyclable
Designed to break down properly, not just claim to

Local-first production
Reducing unnecessary freight where possible

The goal isn’t to tick a sustainability box. It’s to genuinely reduce waste while keeping performance high.

Because if it doesn’t work as packaging, no one’s using it anyway.

How to Choose the Right Mailer Box 

If you’re unsure what size you need, keep it simple. Start by asking yourself these questions: 

What are you shipping?

• Are your items fragile or not?
• Are they heavy or lightweight?

How often you ship?

• Daily orders need efficiency
  
• Occasional orders need flexibility

Do you want to show your branding?

• Plain is fine
  
• Custom becomes valuable as you scale

What are your average shipping costs?

• Smaller boxes = lower costs
• Oversized boxes = wasted money

For example:

For Clothing brands, try medium Mailing Box or EcoMailers depending on the garments

If you offer Subscription boxes, try custom printed boxes for presentation and branding

If you are shipping fragile items, select the closest fitting box size and protective fill such as Hex Wrap. 

Understanding Your Options: Where Different Suppliers Fit

If you’ve been looking into mailer boxes in Australia, you’ve probably noticed something pretty quickly, everyone offers something slightly different.

That’s because most suppliers aren’t actually built for the same type of business.

Some are set up for bulk wholesale.
Some focus on branding.

So instead of asking “who’s best”, it’s more useful to ask: Who is this built for?

Here’s a simple way to think about it.

Bulk-first suppliers

Some packaging companies are designed around large volume orders.

They typically offer:

• Lower unit pricing at scale
• Higher minimum order quantities
• Longer production timelines

These can make sense if you’re ordering thousands of units at a time and planning well in advance.

Where they tend to fall down is flexibility. Smaller or fast-growing brands can end up over-ordering or waiting weeks for stock.

Branding-first suppliers

Other suppliers lean heavily into custom packaging and presentation.

You’ll usually get:

• Strong print options
• More design flexibility
• Higher price points

These are great if your packaging is a big part of your brand experience, but they’re not always the most practical for everyday fulfilment or fast-moving inventory.

Where HeapsGood fits

HeapsGood sits intentionally in the middle, focusing specifically on:

• Practical packaging for ecommerce
• Strong sustainability without compromising usability
• Fast turnaround and low minimums

In other words, packaging that works day-to-day, not just in theory.

It’s built for brands that are shipping regularly, growing quickly, and don’t want to overcomplicate things.

Frequently Asked Questions

What sizes does Australia Post accept?
Australia Post accepts a wide range, but pricing depends heavily on size and cubic weight.

Are HeapsGood mailer boxes recyclable?
Yes. They’re fully recyclable, compostable and made from recycled materials.

Do you offer custom printing?
Yes! We offer custom box printing from sizes XS - L. You can print on up to four panels, with the option to print double sided for a small extra cost. Find out more here.

What’s the turnaround time?
Standard boxes are available quickly, and are typically dispatched within three business days. Custom varies depending on volume.

Are eco-friendly boxes more expensive?
Not significantly, especially when factoring in shipping efficiency.

Can I use these for international shipping?
Yes, as long as weight and durability requirements are met.

What’s the minimum order?
Quantities start as low as 25 boxes in each size. These are low entry points compared to most bulk suppliers.

Are they strong enough?
Yes. Designed to handle typical ecommerce loads up to around 4kg.