What Are Booklet Envelopes?

Meet the writer: Karen Pieper

Hi, I'm Karen! I've been in the industry for 18 years and can't wait to share my perspective on all things direct mail. I'm currently the Digital Marketing Manager at Letter Jacket Envelopes and deal with tasks from managing the website, facilitating conversations with customers, and much more!

Booklet envelopes are medium-sized envelopes designed for larger, unfolded materials that would not fit in a standard #10-sized envelope. They are perfect for sending small brochures, pamphlets, booklets or stacks of unfolded, unbound paper. Booklet envelopes can also be used to send mixed media, such as a refrigerator magnet, some fliers and a postcard-sized notice, all in the same flat mail package.

Brands can take advantage of booklet envelopes’ atypical form factor to draw attention to their direct mailing campaigns. By enticing recipients with the prospect of something more substantial than a typical mailed flier, you can increase open rates while providing critical surprise and delight elements that leverage the physical appeal of direct mail.

Booklet Envelope Basics

Booklet envelopes differ greatly from the typical diamond-cut and folded-form factor of standard envelopes like the #10 envelope and the A4. Instead, the paper stock is cut and folded almost like a manila folder, with two glued side flaps and an unglued sealing flap on the top.

Note that unlike most larger envelopes, the sealing flap is located along the longer side. This characteristic makes it easier to fill the envelopes since more of the envelope interior is accessible. In other designs, the booklet must be carefully guided vertically during stuffing, a time consuming process that often creates tears and waste.

Typical booklet envelope sizes include:

    • 6 x 9 — Best for “cute-sized” smaller materials like pamphlets, booklets, small catalogs or small printed fliers. This form factor is just slightly less wide than a #10 envelope and around two inches taller.


  • 9 x 12 — The perfect size to fit normal 8 1/2” x 11” papers unfolded. Accountants and tax firms can use these envelopes to send printed tax return documents, for instance. Medium-sized magazines can also be sent.
  • 10 x 13 — Oversized for larger materials, including large-format catalogs. Not as common as the booklet’s other styles since they can be bent during postage, but are excellent for making an impact or shipping premium materials via mail.


How to Use Booklet Envelopes

The best use for booklet envelopes is sending high-quality printed and bound materials like brochures, booklets, pamphlets or small magazines. The size difference between the booklet envelope and a regular #10 will prompt curiosity, encouraging even the most cynical recipients to take a peek inside the envelope before they can recycle it.

Use this moment to your advantage by making your printed materials colorful, engaging and dynamic. Diagrams, cartoon-style drawings, eye-catching photography and enticing offers all make best use of small-format bound materials. Likewise, reference guides can make employ existing educational content in a pocket-ready format to regularly reinforce branding every time the recipient consults it.

You can also use mixed media. Print a postcard-sized explainer on heavier cardboard stock with elegant graphic design to encourage recipients to hang onto the piece. Go for artistic appeal since this will encourage retention. Other mixed media approaches include interactive materials similar to self-mailers that must be assembled. The more time a recipient spends with the material, the greater chance of seeing conversion actions or direct returns from the campaign.

As always, ensure that your booklet envelope prominently features your company logo and other branding materials to connect your direct mail campaign with other channels and efforts.

You can take a look at Letter Jacket’s high quality booklet envelopes, available in multiple sizes. Each one can also be printed with custom art courtesy of Letter Jacket’s intuitive ordering system.


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