Envelope Styles & Sizes

There are many different envelope types and sizes available to use. They differ by size, flap type, and the many window positions.


There are various parts of an envelope. Variation of these parts create different envelope styles. Envelope Parts
Examples of Open Envelopes The envelopes with the opening and seal slap located on the SHORT dimension are called Open End envelopes. The ones with the flap on the LONG dimension are colled Open Side envelopes. These envelopes are ideal for automatic insertion applications.

REMEMBER not all envelopes are machineable, which can save time and money. If you are unsure, please call PDM to discuss.

Flap Styles

The flap is the part of the envelope that is folded to seal it. The main flap shapes are shown.

REMEMBER flap shape & size can make an envelope not machineable. If you are unsure, please call PDM to discuss.
Envelope Flap Styles

Sizes and Styles

There are two main envelope standard systems. The first is used in the United States. (US envelopes are often referred to as Standard.) The other is the ISO metric system used in Eurpoe and other parts of the world.

Envelopes sizes vary from very small to very large and there are many sizes in between. Here are a few of the commonly used sizes. (Sizes are listed in inches and the shortest dimension is first.)
Commercial: These are the most popular envelopes for business correspondence. They have a commercial flap style. Commerical Envelopes Sizes
Annoucement: These are common envelopes used for annoucements, invitations, cards, small booklets, brochures or other promotional pieces. Flaps are ususally pointed or flat. Annoucement Envelope Sizes
Baronial: These are more formal, deeper envelopes used for annoucements, invitations and cards. Flaps are ususally pointed. Baronial Envelope Sizes
Booklet: These envelopes are often used for sending catalogs and folders. Booklet Envelope Sizes
Catalog: These envelopes are mainly used for sending catalogs, magazines and reports.

There are also Metal Clasp, Coin and other styles not listed here, because they are typically not suitable for printing.
Catalogs Envelope Sizes


Window envelopes are most often used for bills, checks and marketing purposes. The are very cost efficient since the name and address shows through the window, eliminating the need for additional printing of the address on the envelope.

NOTE: The sizes and positions of windows vary greatly depending on the manufacturer.

Single-Window: The most common window size (and recommended by the USPS) is 1-1/8 x 4-1/2, and the position is 7/8 inch from the left and 1/2 or 5/8 inch from the bottom. Single Window Envelopes
Double-Window: These envelopes are often used for checks and invoices. Check, #9 and #10 are popular sizes. Double Window Envelopes