Envelope Size Guide: Commercial, Baronial…

Common envelope sizes are easy to put into an envelope size chart.

There is a wide range of envelope styles and sizes of envelopes. The most common sizes of every envelope type can take A4-sized paper when the paper is folded a maximum of four times. The largest sizes can take an A4 sheet of paper unfolded and sometimes are given names based on the standard paper sizing system. 

Envelope Size Guide: Commercial, Baronial size-charts.com
Image Source: The Supplies Shops

The outer envelope dimensions are about a maximum of ¾ inches smaller than the dimensions of the paper that can be inserted into the envelope. All standard envelope dimensions are in inches. 

Jump right into the Frequently Asked Questions

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Commercial Envelope Size Chart

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This style is sometimes called an airmail envelope. They are designed for automatic insertion making them a good choice for small-size documents like personal checks, standard business checks, personal correspondence, single-page business correspondence, and simplified formal announcements.

They are usually self-seal business envelopes with commercial flaps that have an adhesive strip and come with a peel-and-stick concept for easier machine insertion. Most window envelopes and white envelopes are chosen from one of these sizes. These are the most common sizes in the world and are the yardstick for the standard business envelope sizes.

NameSize (In)Size (mm)
9 (Policy)4×9101.6×228.6

Baronial Envelopes Size Chart

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Baronial envelopes usually have a tall and pointed envelope flap. They are large-sized envelopes with bright colors and textures. The attractive colors and triangular contour flaps make them popular invitation envelopes and for personal effects like greeting cards.

NameSize (In)Size (mm)
1 Bar3.63×5.1392.2×130.3
5 Bar4.13×5.5104.9×139.7
5½ Bar4.38×5.75111.3×146.1
6 Bar4.75×6.5120.7×165.1
7 Bar5.25×7.25133.4×184.2
8 Bar5.5×8.13139.7×206.5
9 Bar5.75×8.75146.1×222.3
10 Bar6×9.5152.4×241.3

Catalogue Envelopes Size Chart

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A catalog envelope is a perfect envelope for a large paperweight. These jumbo envelopes are the biggest envelopes and are used for bulky documents like catalogs, magazines, and legal documents.

NameSize (In)Size (mm)

Announcement Envelopes Size Chart

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Announcement envelope sizes are meant to follow a guideline of paper sizes.

NameSize (In)Size (mm)

Square Envelopes Size Chart


This type of envelope is the only one that is not among the standard business envelopes and therefore has little use in the commercial industry. It is characterized by square flaps and all four sides being equal in length.

NameSize (In)Size (mm)

Booklet Envelopes Size Chart

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These are wide-clasp envelopes. Wide document sizes for booklet envelopes have to lead to the envelopes mostly being opened on the wide side.

NameSize (In)Size (mm)

Remittance Envelopes Size Chart

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This is the banker’s envelope. The smallest ones qualify as a mini envelopes and are usually used as bank deposit envelopes for cash, letter paper, single-page bills, and any other piece of paper with negligible paper weight info.

NameSize (In)Size (mm)

Learn more about different Envelope Types and Sizes (video)

Envelope Size Guide | DL, C6, C5, C4 by All Colour Envelopes

Frequently Asked Questions

What is a standard envelope size?

There a several standard sizes but the size that is mostly sold all over the world as an “envelope” is the size 10 commercial envelope. Its measurements in inches are 4⅛ × 9½.

What size is an A4 envelope?

A4 is a paper size and the proper term for an envelope designed to contain A4 paper without folding or creasing the paper is the term “C4”. A C4 envelope measures 12.8 inches by 9 inches. In millimeters, this is equivalent to 334×229.

What size are A3 envelopes?

A3 envelopes are sold with the size marking “C4”. These envelopes have inches measurements of 18×12.8 or a millimeter measurement of 458×324.

What envelope size is A5?

A5 envelopes are better known as C5 and their measurements in inches are 6.4×9. This translates into millimeters as 162×229

Is C5 the same as A5?

A5 is the name of a particular standard size of paper. While C5 is the envelope that is meant to contain A5 paper as one whole sheet without folding or creasing the edges.

What’s bigger A5 or A6?

A5 is bigger than A6. Remember, the larger the number in the sizing scheme, the smaller the paper

What is a standard-size envelope for USPS?

Although there are several USPS envelope sizes, there are two general sizes used regularly by USPS for the majority of their shipping. One can say that there are two standard sizes. The smaller of the two sizes have dimensions in inches to be 3.5×5. it is almost identical to the size of A1 announcement envelopes. The larger size has dimensions of 6⅛×11½ inches. It is almost identical to a commercial envelope of size 16.

Which size envelope should I use?

If you know the ISO size of the paper or document that you plan to put in the envelope, then you can easily choose an envelope. The envelope size is always indicated with the same number as the paper size but with the letter “C”. An A4 paper will fit inside a C4 paper without folding or creasing and an A6 paper will fit inside a C6 paper without folding or creasing; you get the picture.

Will the size of the envelope affect shipping costs?

There are different types of mailings. Most shipping methods are more concerned about the weight of the package when deciding on a price, in this case, the physical size of the envelope doesn’t matter. However, if you are bulk shipping, then you may be charged per box of envelopes; in this case, you have to use the smallest sizes possible.

What can I ship or post with envelopes?

Paper, cards, light jewelry, basic accessories, and anything else that can be held up by paperweight.

What is the best envelope size?

There really isn’t one size that is the best. What matters is the proper protection of the content. You must not have folded the content more than three times.

What is the smallest envelope possible?

The smallest envelopes are popular when shipping a box of envelopes. They are called mini envelopes or coin envelopes and they are usually made in custom sizes. 

What can I use instead of envelopes?

In case you plan to ditch envelopes altogether, you can use plastic files. They are usually made of the thin film.

Are envelope sizes universal?

Yes, all envelopes sold in both physical and online stores are manufactured to the sizes of the envelope charts above.


If you have the right size envelope and enough thickness of material for your envelopes to hold its content, you have little of anything to worry about.

Let’s know if we have been able to help by leaving a comment and don’t hesitate to share the article.

Picture in this post is by Erica Steeves on Unsplash

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