Envelopes are among the most ubiquitous kind of packaging. Paper envelopes have been used for thousands of years as a means to store and protect documents and currency. Today, envelopes travel the globe, carrying everything from business invoices to greeting cards to wedding invitations.
Because their contents vary in size and weight, envelopes also come in all shapes, sizes, and styles. But because the intended use of most envelopes is mailing, there are some important sizing standards to pay attention to. Especially if you want your mail to arrive safely at its destination without costing more than it needs to.
Furthermore, different envelope styles serve different purposes. Business envelopes give a different impression than square envelopes; and window envelopes have a very different application than invitation envelopes.
This guide to common envelope sizes and styles will help you understand the many different envelope types and their typical uses.
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What is the standard envelope size?
When most people think of a “standard envelope,” they are imagining a No. 10 commercial envelope. This is the type of envelope typically used for business correspondence, and it probably makes up the majority of mail you receive.
No. 10 commercial envelopes measure 9½ x 4⅛ inches (or 241 x 105 millimeters). Their size makes commercial envelopes ideal for mailing correspondence with normal A4 or 8½” x 11″ printer paper – the document can be folded into thirds to fit neatly inside.
Commercial envelopes typically have a square flap or a pointed flap. They may also have a plastic window on the front through which the recipient’s address can be seen.
But the truth is, there is no single standard for envelope sizes. Paper sizes and dimensions vary, and so envelope sizes and dimensions must vary as well.
Here is an overview of the six most common styles of envelopes used in mail correspondence, the standard dimensions they come in, and their typical uses:
Commercial Envelopes
Commercial envelopes, also known as business envelopes, are designed specifically for use as mailing envelopes.
Commercial envelopes have dimensions uniquely suited to common standard paper sizes. The most common printer papers and letterheads can be folded to a third of their height in order to fit neatly into a standard commercial envelope.
Commercial envelopes seal lengthwise, with the open end at the top. They may have a pointed flap or a square flap.
While it is possible to obtain commercial envelopes with different paper weights and colors, the vast majority of commercial envelopes are a standard white, off-weight, or gray. That said, commercial envelopes made from recycled paper are widely available.
Commercial Envelope Size Chart
| Envelope Type | Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| No. 6½ | 6.25″ x 3.5625″ | 6″ x 3.3125″ |
| No. 6¾ | 6.5″ x 3.5″ | 6.25″ x 3.325″ |
| No. 7¾ (Monarch) | 7.5″ x 3.875″ | 7.25″ x 3.625″ |
| No. 9 | 8.875″ x 3.875″ | 8.625″ x 3.625″ |
| No. 10 | 9.5″ x 4.125″ | 9.25″ x 3.875″ |
Announcement Envelopes
Announcement envelopes, also called A-Style envelopes, are designed to contain personal mail and greetings. Common uses for announcement envelopes include greeting cards, personal correspondence on decorative stationary, notecards, save-the-dates, and invitations.
Announcement envelopes seal lengthwise. The open side has a deep, square flap. They are often available in a wide variety of colors and paper weights in order to match with your stationary. Specialty announcement envelopes may have both an outer envelope and an inner paper lining in a different color or texture.
Announcement Envelope Size Chart
| Envelope Type | Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| A2 Envelopes | 5.75″ x 4.375″ | 5.5″ x 4.125″ |
| A6 Envelopes | 6.5″ x 4.75″ | 6.25″ x 4.5″ |
| A7 Envelopes | 7.25″ x 5.25″ | 7″ x 5″ |
| A8 Envelopes | 8.125″ x 5.5″ | 7.875″ x 5.25″ |
| A10 Envelopes | 9.5″ x 6″ | 9.25″ x 5.75″ |
Baronial Envelopes
Like announcement envelopes, baronial envelopes are designed to contain personal correspondence. Typical uses of baronial envelopes include greeting cards, personal correspondence on decorative stationary, notecards, save-the-dates, and invitations.
In addition to standard sizing variations, there is one major difference between baronial envelopes and announcement envelopes: the flap. Baronial envelopes have a pointed flap, while announcement envelopes have a square flap.
Baronial envelopes seal lengthwise. The depth of the flap, as well as the color and paper type, vary greatly in order to offer a wide range of aesthetic choices. Specialty baronial envelopes may have both an outer envelope and an inner paper lining in a different color or texture.
Baronial Envelope Size Chart
| Envelope Type | Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| 4 Bar | 5.125″ x 3.625″ | 4.875″ x 3.375″ |
| 5 Bar | 5.625″ x 4.125″ | 5.375″ x 3.875″ |
| 5½ Bar | 5.75″ x 4.375″ | 5.5″ x 4.125″ |
| 6 Bar | 6.5″ x 4.75″ | 6.25″ x 4.5″ |
| 7½ Bar | 7.5″ x 5.5″ | 7.25″ x 5.25″ |
Catalog Envelopes
Catalog envelopes are meant to house documents without the need to fold them. When mailed in a catalog envelope, the documents arrive without creases. This makes catalog envelopes ideal for mailing documents that may be framed or otherwise presented.
The most common type of catalog envelope is the 9″ x 12″ variant, which is perfect for documents printed on classic A4 or 8.5″ x 11″ paper.
Catalog envelopes seal width-wise. For mailing purposes, sticker closure seals are the most common. But for filing purposes, clasp and tie closures are often used.
Catalog envelopes are often a deep yellow color, but grays, whites, and other colors are not uncommon. Catalog envelopes are also commonly available with insulation, such as bubble wrap, to protect their contents.
Catalog Envelope Size Chart
| Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| 6″ x 9″ | 5.75″ x 8.75″ |
| 9″ x 12″ | 8.75″ x 11.75″ |
| 10″ x 13″ | 9.75″ x 12.75″ |
Booklet Envelopes
Booklet envelopes, like catalog envelopes, are meant for containing documents without the need to fold them. The standard sizes for booklet envelopes have the same dimensions as catalog envelopes, except the length and width are flipped. The most common type of booklet envelope is the 12″ x 9″ variant, which neatly houses A4 paper.
The opening flap for booklet envelopes is located on the longer side of the envelope, rather than on the shorter side. They may have a sticker or tear closure for mailing purposes, or a clasp or tie closure for filing purposes.
Booklet envelopes may be made of paper, or cardboard for extra rigidity. Many of the FedEx express mail envelopes are booklet-style.
Booklet Envelope Size Chart
| Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| 9″ x 6″ | 8.75″ x 5.75″ |
| 12″ x 9″ | 11.75″ x 8.75″ |
| 13″ x 10″ | 12.75″ x 9.75″ |
Remit Envelopes
Remit envelopes, also known as remittance envelopes, are typically used for donation, fundraising, or subscription purposes. The envelope itself doubles as an order or donation form, making it easy for donors or customers to fill out and mail off without having to supply their own envelope. And because the fields requiring personal information become concealed when the envelope is closed, remit envelopes offer more privacy than a postcard.
When printed magazines were common, there would often be a remittance envelope tucked into the pages of the magazine with which readers could subscribe. The envelope would come pre-printed with the recipient address and postage; the customer could then fill out their personal information on the closure flap, enclose a check, and seal the envelope.
Today, remit envelopes are still valuable for charitable organizations. And because remittance envelopes can be customized for each individual campaign, they offer a sort of analog “marketing automation” opportunity. It is easy to track the performance of different fundraising efforts with remit envelopes!
Remit Envelope Size Chart
| Envelope Type | Envelope Width x Height (Inches) | Insert Width x Height (Inches) |
| No. 6¾ | 6.5″ x 3.625″ | 6.25″ x 3.375″ |
| No. 9 | 8.875″ x 3.875″ | 8.625″ x 3.625″ |
More Printing Terminology & Sizing Standards Resources
Learn more about commercial printing terminology and sizing standards by reading these helpful resources from the Coastal Creative blog:
- Guide to Standard Poster Sizes
- Guide to International Business Card Sizes
- Guide to Standard Paper Sizes
- What is Dye Sublimation Printing?
- What is Collate Printing?
- Sign Printing Materials 101
- Digital Photo Printing Materials 101