Envelope Sizes

Envelope Sizes

If you find envelope sizes confusing then we have an envelope size chart to help you understand the different types and sizes of envelopes. Some envelope sizes are used a lot more than others such as the #10 envelope and the #9 envelope size.

It is important for you to know that the same paper weight as loose leaf paper e.g. (80 gsm) goes into the construction of envelopes. You should pay careful attention to the weight of an envelope as thicker envelopes are more robust. But additional weight can mean more expensive postage.

Envelope Types

There are different types of envelopes and some are more suitable for business use. Some envelopes use the “A” series of sizes and some just have a numbered range. When you are choosing an envelope for your mailings choose mailing envelope sizes that are a quarter of an inch bigger than what you are going to mail. This will make things a lot easier for you.

So you need to make the right decision with the types of envelope available. Do you need an “A” size or a “C” size? What about a business and correspondence type envelope or how about announcement envelope sizes?

Here are some of the different types of envelopes:

  • Standard
  • Booklet
  • Catalog
  • Square
  • Square flap
  • Contour flap
  • Regular
  • Window
  • Open end
  • Clasp
  • Remittance
  • Mini
  • Lined
  • Document
  • Baronial (usually used for invitations and formal announcements)


Size of a #10 Envelope

The #10 envelope often confuses people. The A10 envelope size is not the same as the #10 envelope size. People often ask “what size is a number 10 envelope?” Well the dimensions of a #10 envelope are 4 1/8 inches by 9 ½ inches. People use size 10 envelopes a lot so it is important that you know the envelope sizes #10.

We will take a look at the sizes of envelopes here and you can use the appropriate envelope sizes chart to make your choice. It is good that there are standard envelope sizes because a common question is “what size is a business envelope?”  You will learn the standard business envelope size here as well as letter envelopes size and a return envelope size.


Business Envelope Size Chart

Business and Commercial Envelopes

Business and commercial sized envelopes are among the most popular for business use. They are convenient for machine use and you can go for a side seam or commercial flap with most machines. A lot of machines will also accept the wallet flap style. If you want to be a bit different then you can go for square flaps but not many machines will support this style.

Type Size
6 ¼ 3 ½ inches by 6 inches
6 ¾ 3.625 inches by 6 ½ inches
8 5/8 3.625 inches by 8.625 inches
7 3 ¾ inches by 6 ¾ inches
7 ¾ (Monarch) 3.875 inches by 7 ½ inches
9 3.875 by 8.875
9 (Policy) 4 inches by 9 inches
10 4.125 inches by 9 ½ inches
DL 4.313 inches by 8.625 inches
11 4 ½ inches by 10.375 inches
12 4 ¾ inches by 11 inches
14 5 inches by 11 ½ inches
16 6 inches by 12 inches


People often ask “what size is a 9 envelope?” Well you can see that there are two #9 envelope dimensions and the size of #9 envelope depends on whether you want the standard or policy version. The policy 4 x 9 envelope is slightly larger. The #11 envelope size and the #14 envelope size are popular choices for larger mailings.


Booklet Envelope Size Chart

Booklet Envelopes

The booklet style envelope is popular for mailing brochures and other types of sales material as well as annual reports. Most mail machines are able to use the open ended style to automatically insert materials.

Type Size
3 4 ¾ inches by 6 ½ inches
4 ½ 5 ½ inches by 7 ½ inches
5 5 ½ inches by 8.125 inches
6 5 ¾ inches by 8.875 inches
6 ½ 6 inches by 9 inches
6.625 6 inches by 91/2 inches
6 ¾ 6 ½ inches by 9 ½ inches
7 ¼ 7 inches by 10 inches
7 ½ 7 ½ inches by 10 ½ inches
9 8 ¾ inches by 11 ½ inches
9 ½ 9 inches by 12 inches
10 9.5 inches by 12.625 inches
13 10 inches by 13 inches


The 6×9 envelope size is a popular choice of booklet envelope. The 6 envelop size is often used to mail smaller materials as is the 6 ¾ envelope size. Please note that the envelope sizes #10 in the booklet style is different to the business style.


A Series Envelope Size Chart

A Series Envelopes

More and more people are using “A” series envelopes now. “A” series envelopes come under the ISO 216 standard and used throughout the world.

Type Size
A0 33.1 inches by 46.8 inches
A1 23.4 inches by 33.1 inches
A2 16 ½ inches by 23.4 inches
A3 11.7 inches by 16 ½ inches
A4 8.3 inches by 11.7 inches
A5 5.8 inches by 8.3 inches
A6 4.1 inches by 5.8 inches
A7 2.9 inches by 4.1 inches
A8 2 inches by 2.9 inches
A9 1 ½ inches by 2 inches
A10 1 inch by 1 ½ inches


You will note that the A2 envelope size is smaller than the A1 and that the A7 envelope size is smaller than the A6 envelope size. Basically the envelopes get smaller by their “A” numbers. The A4 envelope size is popular because you can insert a piece of A4 paper flat. A5 envelope sizes are also popular because they are half the size of A4 paper.


FAQ About Envelope Sizes

What is a legal size envelope?

You will normally find that legal sized envelopes are used for legal documents that have 8 ½ inches by 14 inches dimensions. Most legal envelopes measure 9 ½ inches by 15 inches so that they will easily accommodate legal documents.

What size envelopes for 5×7 card?

You can purchase special “notecards” envelopes and the one to go for here is the A7 size which is normally 5 ¼ inches by 7 ¼ inches.

What size is an A7 envelope?

The standard A7 envelope size is 2.9 inches by 4.1 inches. This is often confused with the popular announcement/notecard A7 size which is usually 5 ¼ inches by 7 ¼ inches.

What is the #12 envelope size?

The business #12 envelope size is 4 ¾ inches by 11 inches.

What is the #6 envelope size?

There is a #6 envelope in booklet style which measures 5 ¾ inches by 8.875 inches.

What are the A6 envelope dimensions?

The A6 envelope measures 4.1 inches by 5.8 inches.


Envelope Templates

You can find templates of various envelopes sizes by going here