A Guide to Envelopes



Envelopes are often overlooked and underrated. Usually overshadowed by the documents they house, they tend to be treated as an afterthought. However, considering that envelopes are the very object that ensures your letter, document or card arrives as intended at their destination, we should learn to pick the right ones.


Fun fact: The earliest form of an ‘envelope’ was used by the ancient Babylonians. Five or six thousand years ago, messages were written on clay tablets. Once the tablets had been baked to harden, they would then be covered with more clay and baked again. To ensure the security of the message, the outer layer of clay had to be broken to reveal the inner tablet.


One of the basic attributes of an envelope is the window. A ‘window faced’ envelope is ideal for letters that have the recipient’s address printed on them, as the address can show through the window. An envelope without a window is known as a ‘plain faced’ envelope. This attribute is usually an option for most types of envelopes.


The different types of envelopes

There are many types of envelopes designed to meet different needs. Below are some of the more common and readily available ones.

Banker Envelopes

A banker envelope has a triangular flap on the long edge, and is traditionally used in the greeting card industry. It is also popular for personal use notes, letters and cards.

Pocket Envelopes

Pocket envelopes open on the short edge. Available in a variety of shapes, sizes and colours, these envelopes are commonly used in all applications.

Booklet Mailer Envelopes

These are C4 or C5 envelopes that open on the long edge, making it easy to enclose thick stacks of paper. Booklet mailer envelopes are often used for brochures, catalogues or multi-page documents.

Wallet Envelopes

Wallet envelopes come with a rectangular closure flap on the longer side, and are typically used for flat A4 sheets or booklets. This is one of the more popular envelope types in the market.

Padded Envelopes

If you are sending something fragile through the mail, padded envelopes come in handy. Lined with cushioned packaging material, these envelopes provide the right amount of protection and ensure your delivery arrives intact.

Security Envelopes

Security envelopes are designed for sending sensitive information through the mail, such as cheques or medical records. It comes with a cross-hatched blue or black pattern inside that prevents the content within the envelope from being seen when held up to the light.


Common envelope sizes

  • C4: Fits an A4 sheet. Ideal for documents that should not be folded, such as catalogues and tenders.
  • C5: Fits an A5 sheet or A4 sheet folded in half.
  • C6: Fits an A5 sheet folded in half, or A4 sheet folded into quarters.
  • DL: Fits an A4 sheet folded in thirds. Common for promotional materials such as brochures and flyers.


Common types of seals

Lick Stick (also known as Gummed)

These envelopes have a water soluble gum lined along one edge of the closing flap. To seal, just moisten the adhesive and press shut. This is one of the most common sealing methods.


To seal these envelopes, remove the covering strip to reveal an adhesive on the flap. Once the strip is peeled off, close the flap and press against the back of the envelope. This is one of the most secure ways to seal an envelope.

Press Seal (also known as Self Seal)

This type of seal has a strip of adhesive on each flap, and when pressed together would seal the envelope. These envelopes sometimes have security slits which will cause the flap to rip if the seal has been tampered with.


What about the colour of the envelope?

White envelopes are the most common envelopes, and can be purchased in different styles. Most businesses choose to use this when sending official letters and documents, because white gives off a professional feel.

The next most common colour is brown. As brown is darker than white and less see-through, it is useful for sending important documents.

Besides white and brown, envelopes also come in all shades and hues. Whether you’re after pastels or vibrant colours, there is always a suitable envelope colour for your cards, invitations and campaigns.

A tip for businesses:

Use brightly coloured envelopes to make a bold statement when it comes to marketing materials. Recent research has found that a stylish coloured envelope is up to 9 times more likely to be opened compared to a plain white or brown one.


With so many choices available when it comes to envelopes, there is definitely one that suits your business needs. But, in the event you cannot find the right product, we can create it for you!

For custom envelopes, please contact us through our enquiry form or call 1300 554 690.