Envelope Sizes & Styles | Comprehensive [2022 Guide]

When you get ready to mail a letter, you might think that an envelope is just an envelope. However, there are likely many more sizes and types of envelopes than you imagined. The size and style of the envelope you use likely depend on the item you are mailing. The type of envelope used to mail a greeting card is different from the kind of envelope that you would use to send a payment. So, what are some common envelope sizes, and when would you use each of them? Keep reading as we give you all those details in our envelope size guide below.


Common Envelope Sizes & Styles

As we already mentioned, envelopes are available in many sizes and styles. If you need a specific type of envelope, you can probably find it somewhere. However, many common types and sizes are available at almost all office supply stores. Here are some of the most common envelope sizes and styles.


— Business Envelopes

Business envelopes are likely the most common envelope found in mailings today. Some people also refer to these envelopes as regular envelopes. The most common business envelope size is the A10 envelope. This particular size of business envelope measures 4 1/8″ x 9 1/2″. People use the popular #10 envelope size to send all types of business correspondence, such as letters, documents, checks, and other items. In addition, many people use these for personal letters as well.

Business envelopes feature a solid front and a basic flap on the back. They can be purchased in a variety of colors, and you can also find them with many different features. Some of these envelopes contain a self-adhesive flap, and you can also find them with security features that make it more difficult to see the contents of the envelope.


— Square Envelopes

Square envelopes are likely the next most common type of envelope in use today. These envelopes feature a solid front with a more elegant square flap on the back. People use these envelopes to send a variety of items, from greeting cards to announcements. Square-flap envelopes are also commonly used as invitation envelopes. They are used for wedding invitations, graduation invitations, and other types of invitations.

When looking at an envelope size chart, you will see many different square-flap envelopes, or A-style envelopes, there. A2 envelopes, A6 envelopes, and A7 envelopes are some of the most popular sizes of square envelopes. The measurements of those envelopes are as follows. The A2 measures 4 3/8″ x 5 3/4″. The A6 envelope measures 4 3/4″ x 6 1/2″, and the A7 measures 5 1/4″ x 7 1/4″. You can also find square-flap envelopes available in the popular #10 envelope size, but the A2, A6, and A7 are more popular in this style. Purely square envelopes are available in square sizes from 3 1/4″ x 3 1/4″ to 8 1/2″ x 8 1/2″.


— Booklet Envelopes

As the name implies, these envelopes are commonly used to send booklets, catalogs, annual reports, or other sheets of paper. Booklet envelopes feature a flap along the long side of the envelope. This makes it easy to slide a booklet into the open side of the envelope without damage. Standard envelope sizes for booklet envelopes include 6″ x 9″, 9″ x 12″, and 10″ x 13″. You can also find these mailers available in other sizes to accommodate the particular paper size associated with the booklet or catalog you need to mail. These envelopes can also be purchased in several different colors as well.


— Catalog Envelopes

Catalog envelopes are also called open-end envelopes. These are similar to booklet envelopes, but catalog envelopes feature the flap and opening along the short end of the envelope. This makes it easy to insert catalogs or other contents into the envelope. They are available in a variety of sizes, such as the 2 1/4″ x 3 1/2″ coin envelope all the way to a large 14″ x 18″ catalog envelope.

Catalog envelopes can feature either a window-front or a solid front. In addition, you may find self-adhesive flaps, traditional gum flaps, or clasp flaps. These envelopes can be purchased in a variety of different colors as well to meet your mailing needs. Most of these envelopes will require extra postage from the postal service due to their large size.


— Baronial Envelopes

Baronial envelopes are also popular when mailing invitations and other formal correspondence. They feature a pointed flap instead of the traditional and less formal square or contoured flap. The most common size Baronial envelope is likely the 4 BAR size. This envelope measures 3 5/8″ x 5 1/8″. The second most common size is the A2 which measures 4 3/8″ x 5 3/4″. However, you should know that these are not the only sizes available. You can find baronial envelopes in many other sizes as well as different colors. Since these envelopes are typically used for mailing formal invitations, you can also purchase them in metallic colors or styles with textures. Usually, they are made from high-quality or heavyweight paper.


— Announcement Envelopes

People use a couple of different styles of envelopes for announcements. Most commonly, the announcement envelope features a solid face with a square flap. You may decide to use a square envelope for your announcements. In that case, you can find them available in sizes as small as 3 1/4″ x 3 1/4″ to as large as 10″ x 10″. Commonly, you purchase these envelopes at the same time as your announcement so that you can get them to match. That could be in style, color, or texture. You can find announcement envelopes in many different colors and textures.


— Window Envelopes

You have likely seen window envelopes often included with billing statements or direct mail from fundraising organizations. These are popular commercial envelopes that are often used as remittance envelopes. Commonly, they are placed into an outer envelope and mailed along with a billing statement. The window envelope, or reply envelope, allows a customer to easily include payment and remit the amount back to the business without even addressing the envelope. The billing statement shows the address through the window, and it makes it easy for the mail piece to be delivered by the postal service.

Unlike other kinds of envelopes, window envelopes are usually only available in a few different sizes. The most common size is 5 3/4″ x 8″. This size allows it to fit inside a standard A10 envelope when used for business mailings. You can also find window envelopes available in #10 or #9 sizes.


— Specialty Envelopes

If you are looking for a mailing envelope that has not already been discussed, then you might need to look for a specialty envelope. Perhaps you need to mail small note cards, business cards, or larger brochures. Whatever your need, you can likely find a specialty envelope that will work. You can even find envelopes that are lined with metallic colors inside. You can always work with a supplier to create a custom envelope if you cannot find anything else that fits your needs. Just like when you cannot find a shipping box size that works for you, this allows you to create an envelope that is the exact size needed for your application. You can also choose the type of flap, seal, and opening on the envelope.

Where To Buy Envelopes

One of the most common places to buy envelopes is an office supply store. These stores will usually have a wide variety of types and sizes of envelopes. More than likely, they will have what you need, whether it is for commercial or personal use. If you need a fairly standard size, you can usually purchase them at your local grocery store or pharmacy.

If your business uses a large number of envelopes, then you may benefit from working directly with an online envelope supplier. You may be able to get discounts that will offer better pricing than most office supply stores. These online stores usually have a large inventory of many different kinds of envelopes. In addition, some of them can create custom envelopes for you that will work for your specialty mailing needs.


Cost Of Envelopes

The cost of envelopes varies significantly based on the size, type, and style of the envelope that you purchase. The material also plays a huge role in the cost. Lightweight envelopes with no lining will be significantly cheaper than lined envelopes that feature heavyweight paper material. Here are some common prices.

An A10 envelope made of standard materials will usually cost you somewhere around $0.20 to $0.30 each. Usually, these must be purchased in packs of at least 25 or 50. At the other end of the spectrum, some fancy invitation envelopes can cost as much as $3 to $4 each. As you can see, that gets expensive quickly when you need to mail 100 or more invitations to an event.

The best way to get the best price on your envelopes is to shop around. Visit your local office supply stores and also compare prices with online retailers. Be aware of the material and type of envelope that you purchase. There is no need to purchase heavyweight envelopes if they are not needed. Similarly, don’t pay extra for colors or lining in the envelope unless it is necessary.


The Bottom Line

There are many standard envelope sizes, and there are also some common types that are frequently used. Once you decide on the type of envelope you need, the size options are almost endless. You can even have custom envelopes created if you are unable to locate a size that works for you. Prices range anywhere from $0.20 each to $4.00 each, depending on the style and material of the envelope.


Frequently Asked Questions


Are all #10 envelopes the same size?

Yes, all #10 envelopes should be the same size. A standard #10 envelope should measure 4 1/8″ x 9 1/2″. This type of envelope will easily fit a standard sheet of paper that has been tri-folded. These envelopes are extremely common in the business world, and they are also commonly used for personal correspondence.


What size is a C5 envelope?

A C5 envelope should measure 162mm x 229mm. These envelopes are not commonly used in the United States. They are more common in European countries, like the UK and Australia. These envelopes will fit a standard A4 sheet of paper that has been folded in half.


What is a letter-size envelope?

A letter envelope is typically an A10 or size 10 envelope. This envelope size is one of the most common sizes that you will encounter. They will fit a standard 8 1/2″ x 11″ sheet of paper that has been tri-folded. These envelopes are used for personal letters and mailings as well as many types of business mailings. In addition to letter envelopes, legal-size envelopes are often used for business mailings.

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