Buying envelopes online sounds straightforward until you are staring at a list of size codes, seal types, style names and paper specifications. Get the size wrong and your documents do not fit. Choose the wrong seal type and a high-volume mail-out takes far longer than it should. For schools, councils, government offices and businesses ordering in volume, getting this right the first time matters. Here is what you need to know before you order.
Match your envelope size to what you are sending
Australian envelopes follow the ISO C series sizing standard. Each size is designed to fit a specific paper or card format, folded or flat. Matching the envelope to the contents is the single most important step before placing an order.
DL (110 x 220mm): The standard Australian business letter envelope. Fits an A4 sheet folded into thirds. Used for invoices, letters, formal notices and general correspondence across schools, councils, government offices and businesses.
DLX (120 x 235mm): Slightly wider and longer than DL. A better fit for A4 sheets folded in thirds when a small margin is needed, or for slightly bulkier contents. Commonly used by councils and government agencies to avoid a tight fit on heavier paper stock.
C6 (114 x 162mm): Fits an A4 sheet folded into quarters, an A5 sheet folded in half, or an A6 card flat. Widely used for recycled greeting cards, postcards, invitations and short correspondence. Available from Buyecogreen in packs of 50 or boxes of 450 through the recycled envelopes range.
C5 (162 x 229mm): Fits an A4 sheet folded in half or an A5 card flat. A practical choice for information packs, event programs, certificates and any communication where a single fold is preferable to a trifold.
C4 (324 x 229mm): Fits A4 sheets flat and unfolded. The right choice for large documents, tender submissions, annual reports, contracts and any contents that should not be creased or folded. Buyecogreen stocks C4 recycled envelopes in boxes of 250 with a peel-n-seal closure suited to high-volume institutional despatch.
Square formats (110 x 110mm, 130 x 130mm and 152 x 152mm): Suited to square cards, invitation reply enclosures and seasonal mailings where a standard rectangular envelope does not fit the card dimensions. Buyecogreen’s range covers all three square sizes in 100% recycled brown paper.
Greeting card format (131 x 182mm): Designed to fit standard greeting card sizes flat. Pairs directly with recycled thank you cards and Buyecogreen’s wider recycled cards blank stock range.
Seed or mini pocket (145 x 90mm): A small pocket-style envelope for seed packets, event favours, small gift enclosures and RSVPs. Pair with seeded paper products for a fully plantable, zero-waste communication package suited to councils, schools and community environmental events.
Understand envelope styles: wallet, banker and pocket
Once you have the right size, the style tells you how the flap is positioned and how the contents are inserted.
Wallet style: The flap runs along the long edge of the envelope, and contents slide in from the side. Common for C6 and C5 formats and the preferred style for greeting cards, postcards and correspondence where the card needs to slide in cleanly without bending.
Banker style: The flap runs along the short top edge. A formal style traditionally used for business correspondence and also available in C6 format. Both C6 wallet and C6 banker options are available in the Buyecogreen recycled envelopes range.
Pocket style: Opens at the top with a pocket design suited to larger formats like C4 and C5 where a full document needs to slide in without the opening restricting access. The C4 format in particular uses this style to allow A4 sheets to lie flat inside.
Choose the right seal for your mailing volume
Seal type has a direct impact on processing efficiency, particularly for schools, council mail rooms and government offices handling large volumes.
Lick and stick (gummed): Traditional moisture-activated seal. Low cost and suited to low-volume or occasional use. Not practical for bulk mail-outs where staff are sealing hundreds of envelopes at a time.
Peel and stick or peel-n-seal (self-seal): A strip pulls away to expose a pressure-sensitive adhesive for a clean, fast seal. More consistent and efficient for high-volume processing. Recommended for institutional procurement where regular despatch runs are part of the workflow.
White or brown recycled: choose based on your context
Buyecogreen’s recycled envelopes come in two finishes, both made from 100% post-consumer waste paper and produced in Australia from 115gsm stock.
Brown or grey-brown unbleached recycled: The natural finish of unbleached recycled paper. Well suited to community communications, eco-branded mail-outs, event invitations, sustainability programs and any organisation where the material itself communicates environmental values. Pairs consistently with recycled labels, brown recycled paper and recycled backing and mailing board for a fully natural, plastic-free outgoing mail setup. Note that the shade can vary slightly between production batches due to the recycling mix, which is a normal characteristic of genuine post-consumer recycled paper.
White recycled: For formal institutional correspondence where a conventional white envelope is expected: invoices, government notifications, professional letters and compliance documents. The same 100% post-consumer recycled credentials as the brown range but with a standard white presentation suited to formal correspondence requirements.
Order the right pack size for your volume
Matching your order quantity to your actual usage avoids overstocking formats you rarely use and running short on your most common sizes.
Packs of 50 suit small organisations or teams ordering a new size for the first time. Boxes of 250 to 450 suit schools, council administration teams and government offices with regular or high-volume mailing requirements. For organisations sending branded envelopes, custom printing is available from minimum quantities of 250 to 500 depending on the format. Contact the team for a quote before placing a bulk print order.
For a complete eco-friendly mailing and despatch setup, combine recycled envelopes with recycled labels for addressing, recycled backing and mailing board to protect flat items in transit and recycled business cards and seeded paper for a fully sustainable communications package. Browse the full recycled envelopes range at Buyecogreen or contact the team on 1300 663 488 or at info@buyecogreen.com.au for volume procurement, standing orders and custom print enquiries.
FAQs
What is the standard Australian business letter envelope size?
The DL envelope at 110 x 220mm is the standard Australian business letter format, designed to fit an A4 sheet folded into thirds. It is the size used for most invoices, formal letters, payment notices and general correspondence across Australian businesses, government agencies and schools. Buyecogreen stocks DL recycled envelopes in the recycled envelopes range in both brown and white recycled paper finishes.
What is the difference between a wallet and a banker envelope?
A wallet envelope has its flap along the long edge, with contents inserted from the side, while a banker envelope has its flap along the short top edge, with contents inserted from the top. Wallet style is more common for greeting cards and informal correspondence, while banker style has traditionally been used for formal business correspondence. Both styles are available in C6 format in Buyecogreen’s recycled envelopes range, alongside wallet and pocket styles in other sizes.
How do I know which envelope size fits my greeting cards?
Match the envelope to the flat dimensions of the card, allowing a few millimetres of clearance on each side. A C6 envelope at 114 x 162mm fits a standard A6 card (105 x 148mm) flat with a comfortable margin and is the most common choice for recycled greeting cards, postcards and folded A5 cards. For larger cards, the 131 x 182mm greeting card envelope accommodates standard-sized greeting cards, and full size details are confirmed on each product page.
Are Buyecogreen’s recycled envelopes suitable for standard Australian postage?
Yes. The DL, C6, C5 and DLX formats in the Buyecogreen range are suitable for standard Australian postal services, with DL and C6 qualifying for standard letter postage rates. C5, C4 and larger formats fall under large letter or parcel rates depending on the weight and thickness of the contents. Individual product pages confirm postage rate eligibility for each format and note the standard postage rate where applicable.
Can I order recycled envelopes in bulk for institutional use?
Yes. Buyecogreen supplies recycled envelopes to schools, councils, government departments, childcare centres and not-for-profit organisations across Australia, with box sizes from 50 to 450 depending on the format and custom printing available from minimum quantities of 250 to 500. For standing orders, volume procurement or custom print quotes, contact the team directly on 1300 663 488 or at info@buyecogreen.com.au.