Large Letter Postage:How eCommerce Businesses Can Cut Australia Post Costs at Scale
For eCommerce businesses and companies sending mail in bulk, packaging isn’t just about protection – it directly impacts your Australia Post cost and long-term profitability.
Australia Post enforces strict Large Letter size and weight limits, with very little tolerance. If your packaging doesn’t meet the gauge requirements, your shipment can be reclassified, resulting in a significant increase in letter postage Australia rates.
This article explains what can be sent in an Australia Post Large Letter, how to meet standard post large letter requirements, and which packaging solutions work best for high-volume dispatch operations.
What Can I Send in an Australia Post Large Letter?
To qualify for the Postage Large Letter Australia rate, your item must:
- Drop freely through the Australia Post letter gauge (without force)
- Stay within the maximum size and weight limits
Standard Post Large Letter Specifications:
- Maximum size: 260mm × 360mm × 20mm
- Maximum weight: 500g
- Must only contain flexible materials as the package can get damaged in the sorting machines.
These limits are particularly important for eCommerce fulfilment centres, subscription services, and businesses mailing marketing materials, flexible product samples, flexible spare parts, or documents in volume.
Common industries utilising Australia Post’s Large Letter Postage
E-Commerce / Retailers
Financial Institutions / Banks
Insurance Companies
Charities and Non-Profits
Publishers
Marketing Firms
Why Large Letter Compliance Is Critical for Bulk Shipping
For businesses shipping hundreds or thousands of items per month that are under 20mm thick, staying within the Large Letter category can dramatically reduce Australian postage costs.
- Domestic Large Letters under 250g can cost as little as $5.10.
- Exceed the size or thickness by even a few millimeters, and costs can jump to $10+.
- Outside the Large Letter size and weight guide – the package will be considered a ‘parcel’ and higher costs apply.
- Express Post, Registered Post, and tracking services become significantly more expensive outside the Large Letter category.
Using the correct packaging allows bulk senders to:
- Reduce postage stamp cost,
- Improve fulfillment efficiency, and
- Maintain predictable shipping expenses when using the Australia Post calculator.
Wrap-around Cardboard Mailers
QIKPAK Mailers
A premium mailing option for eCommerce businesses shipping thin but valuable items.
- E-Flute corrugated board for superior protection
- Strong presentation for customer-facing shipments
- Reliable performance in automated packing environments
- Fragile flat products
- Replacement parts
- Items sent via Registered Post
- Items sent via Express Post
Available Sizes
145mm × 130mm and 260mm × 150mm
NOTE: Contents must remain thin enough to stay within the 20mm thickness limit.
Packaging Solutions Designed for eCommerce & Bulk Mailers
We supply industrial-grade mailing solutions designed to help businesses consistently meet Australia Post Large Letter requirements while maintaining packing speed and product protection.
Polycell Mail Tuff
- made up of a kraft paper exterior and bubble lining
- superior lightweight mailing bag ensures postage costs are kept to a minimum
- its composition (tough kraft paper outer in conjunction with a tamper-evident seal) makes it popular as it stands up to tough mailing cycle situations
Best for: Documents, small electronics, accessories and for Fragile items needing cushioning protection.
Check out the product page for more info:
Polycell Maxi Tuff
These mailers are ideal for items needing enhanced protection from moisture, impact, and tearing during transit.
- 3-layer bubble lining provides superior protection from external elements (such as moisture) and cushioning
- Reduced damage in transit
- Self-seal adhesive flap
Best for: Clothing, retail products, ecommerce and similar items.
Available Sizes
Wide range of sizes with some suitable for Australia Post Large Letter requirements.
Check out the product page for more info:
Polycell Courier Tuff
A lightweight mailing solution ideal for optimal surface product production and extra tamper-evidence performance.
Check out the product page for more info:
- made from high quality hot melt adhesive closure
- durable, multi-layer, co-extruded film
- offering additional tamper evident performance
- surface protection
- designed for reduced postage costs
Best for: Items needing surface protection like documents, clothing and non-fragile items.
Polycell EcoPure Courier Tuff
EcoPure Courier Tuff is an ecofriendly and durable option for mailing lightweight items.
- Uses EcoPure technology – a blend of organic ingredients that is added to plastics that has been proven to speed up plastic biodegradation
- High-quality hot melt adhesive closure for extra protection against tampering
- Lightweight
- Various sizes available
Best for:
Protecting the surface of an item during transit and to carry delivery details. Ideal for items such as Apparel, Soft goods, Printed materials, Items already protected internally, or pre-packaged.
Check out the product page for more info:
Polycell Corrugated Mailer
Polycell’s Corrugated Mailer is sustainable, lightweight with self-seal closure and cushion protection.
Best for: those wanting sustainable, lightweight packaging with effective cushion protection (i.e fragile items, documents)
Check out the product page for more info:
Polycell Honeycomb Tuff Mailer
This eco-friendly mailer delivers superior cushioning protection – fully sustainable alternative to bubble mailers.
Best for: delicate or fragile items like glassware, ceramics, electronics.
Check out the product page for more info:
Switch to Sustainable Alternatives!
Padded Jiffy Bags
For a more protective, versatile and economical mailing solution.
- Built-in padding reduces damage in transit
- Lightweight compared to boxes, helping manage Australia Post cost
- Flexible profile to help meet Large Letter thickness limits
- Cost-effective protection for high-volume fulfilment
Best for: Small consumer products, Accessories, Electronics components, Fragile items requiring impact protection
Available Sizes
We have a huge range of sizes available for each Jiffy Bag.
Check out these links for more comprehensive info:
NOTE: Contents must remain thin enough to keep total thickness under 20mm for Large Letter eligibility.
Paper Jiffy Bags
Jiffy Rigi Bag and Jiffy Utility are sustainable and professional mailing options ideal for brands prioritising eco-friendly packaging.
- 100% paper-based and recyclable
- Strong construction with a clean, professional appearance
- Lightweight to support lower letter postage Australia costs
- Self-adhesive closure for fast packing operations
Best for: Clothing and apparel, Soft goods, Books and flat products, Documents and marketing materials
Available Sizes
Wide range of sizes suitable for Australia Post Large Letter requirements.
Check out the product pages for more info:
NOTE: Offers limited cushioning – best for non-fragile or internally protected items.
ShurTuff® Jiffy Bags
A lightweight but durable, cost-effective solution ideal for high-volume, low-risk shipments.
- Extremely low unit cost ($0.10–$0.15, depending on volume)
- Lightweight to help control Australia Post cost
- Simple format for fast packing lines
Best for: Apparel, Soft goods, Printed materials, Items already protected internally, or pre-packaged that require a mailing bag to carry the delivery details.
Available Sizes
190mm × 260mm and 250mm × 325mm
NOTE: Limited protection – best for non-fragile items.
Ask about our Sustainable Alternatives!
Choosing the Right Large Letter Packaging for Your Business
The best packaging solution depends on:
- Product type and fragility
- Monthly shipping volume
- Whether you use standard post, express post, or registered post
- Cost control vs presentation requirements
For eCommerce and bulk senders, standardising the right mailer can lead to major savings in Australia Post cost over time.
Need a Bulk Packaging Solution That Reduces Australia Post Costs?
We specialise in supplying bulk packaging solutions for eCommerce, warehousing, and B2B businesses.
Our team can help you:
- Lower letter postage Australia costs
- Improve packing speed and consistency
- Select packaging that aligns with Australia Post guidelines
Ready to Save on Your Bulk Mail Packaging?
As a single sourcing industrial packaging supplier, our comprehensive range ensures your business needs are meet, no matter your industry. Give us a call to discuss bulk pricing and tailored solutions fit for your business needs.
