Envelope Styles and Sizes

There are plenty of envelope types and sizes available—they differ by size, flap type, may have windows. In this article we’ll describe the most important types of envelopes, though the stress will be made on envelopes, which you can print upon with a regular inkjet or laser printer using Swift Publisher or other similar software.

Construction

This picture illustrates various parts of an envelope. The variations of these parts create different envelope styles.

The envelopes with the opening and seal flap located on the short dimension are called Open End envelopes. Those with the flap on the long dimension are called Open Side envelopes. Such envelopes are ideal for automatic insertion applications.

Flap Styles

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

Sizes and Styles

There are two main envelope standard systems we’re going to review. The first is used in the USA (US envelopes are also often known as Standard), the other is the ISO metric system used in Europe and many other parts of the world. The envelope sizes may vary from tiny to huge, and there are dozens of them of sizes available. Though you’ll hardly use more than 4-5 most common sizes in your everyday practice, it’s a good to have an understanding of other possible styles and sizes.

Standard (US)

The US (or Standard) envelopes are divided in several groups by their style and application. The sizes are listed in inches, the shortest dimension first.

Commercial

These are the most popular envelopes for business correspondence, that we send and receive every day. They usually have commercial flap.
They are mostly used for letterheads, invoices, statements, checks, writing stationery and direct marketing mailings.

Note: The 7 ¾ envelope with pointed flap is also known as Monarch.

Announcement

These are very common envelopes. The flaps are usually pointed or flat.
Mostly used for announcements, invitations, cards, small booklets, brochures or promotional pieces.

Baronial

These are more formal envelopes, are deeper and typically use a pointed flap. They are popular for invitations.

Booklet

These envelopes are mostly used for sending catalogs, folders and the like.

Catalog

This style of envelope is mainly used for catalogs, magazines and reports.

There are also Metal Clasp, Coins, and probably other styles, which are not listed here because they are either rare, too small or too large, or not suitable for printing (such as Metal Clasp).

Window Envelopes (US)

Window envelopes are most often used for bills, though they’re also popular for marketing purposes. They are cost-efficient, since the name and address shows through the window, eliminating the need to address the envelope. Normally translucent plastic is used as the window material. Open window envelopes are growing in popularity as more environmentally friendly, however, they are less secure.

Single-Window Envelopes

Theoretically, nearly each envelope type and size may have a window, this generally depends on the manufacturer. The most common (and recommended by USPS) window size is 1 ⅛ × 4 ½, and the position ⅞ in from left and ½ (often ⅝) in from bottom, but there are lots of variations.

Double-Window Envelopes

Such envelopes are often used for checks and invoices. The three probably most popular envelope sizes with double windows are:

Note: The sizes and positions of windows may vary greatly, and depending on the manufacturer. There are no standards for these (at least which we are aware of).

ISO Envelope Standards

These envelopes are widely used all over the world. The C series was designed to accommodate ISO A paper sizes (see Paper Sizes and Formats Explained). For example, a C5 envelope will accommodate an A5 sheet flat or an A4 folded once. The B series is an alternative, and is much less common than the C series. The sizes are provided in millimeters and in inches (for reference).

Name	Size, mm	Size, in	Content Format and Comments
C3	324 × 458	12 ¾ × 18	A3 sheet; Not very common
B4	250 × 353	9 ⅞ × 13 ⅞	C4 envelope
C4	229 × 324	9 × 12 ¾	A4 sheet; Very common
B5	176 × 250	7 × 9 ⅞	C5 envelope
C5	162 × 229	6 ⅜ × 9	A4 folded once = A5; Very common
B6	125 × 176	5 × 7	A4 folded in quarters; Very common
C6	114 × 162	4 ½ × 6 ⅜	A4 folded in quarters; Very common
DL	110 × 220	4 ¼ × 8 ¾	A4 sheet folded in thirds, A5 sheet folded in half lengthwise; Very common
C6/C5	114 × 229	4 ½ × 9	A4 sheet folded in thirds; Common
C7/6	81 × 162	3 ¼ × 6 ⅜	A5 sheet folded in thirds; Uncommon
C7	81 × 114	3 ¼ × 4 ½	A5 sheet folded in quarters; Uncommon

Note: Although DL is not part of the ISO C series, it is a very widely used standard size.

Window Envelopes

There are no international standards yet for window envelopes. Some countries have set their own national standards, for instance:

Germany: The window is 90 × 45 mm large, and its left edge is located 20 mm from the left edge of the envelope. The bottom edge of the window is located 15 mm from the bottom of the envelope (for C6, DL and C6/C5 envelopes). For C4 envelopes, the top edge of the window should be either 27 mm or 45 mm from the top edge of the envelope.

UK: The window on a DL envelope should be 93 × 39 mm large, and located 20 mm from the left and 53 mm from the top of the envelope.

Addressing and Printing Guidelines

The correct formatting and address position on an envelope is required to facilitate mail processing by optical character recognition equipment, used by many postal services for sorting mail. Machine-readable mail can be sorted automatically, rather than by a human, which results in faster and more accurate delivery.

Here is the picture that illustrates the correct address position:

General Considerations

• Always use the ZIP/Postal code.
• If you’re using software for printing addresses, always print barcodes if they are supported by the software.
• Use simple fonts, such as Arial or Helvetica, and font size over 12 points.
• Avoid using any graphics in the address zone, as it may confuse the optical reading equipment.

When printing addresses on envelopes or labels, it’s recommended that you use a laser printer—ink from inkjet printers is susceptible to moisture, and the address may get blurred or even completely unreadable on the way. However, don’t print on window envelopes with laser printers—the window material will melt because of the contact with the printer’s heating element.

Where to Buy

There are plenty of places you can order envelopes—the post office next to you maybe the most appropriate one. However, you can also order envelopes online—convenient if you’re looking for something special.

USA: [Staples] [Amazon] [Office Depot]
Canada: [Grand & Toy]
UK: [UK Office Direct]
France: [Office Depot]
Germany: [Viking Direkt]

See Also

Envelopes in Wikipedia

An article describing envelope sizes and styles.

Address in Wikipedia

A detailed review of addressing systems used in different countries and general addressing guidelines.

Paper Sizes and Formats Explained

Read about different paper layouts and sizes as well as quick tips for copying and printing.