introduction
There are so many different envelope sizes and types that can be confusing. To help you know how to use different standard envelope sizes and types for different occasions, I will provide a complete guide to eight different types of standard envelope sizes. Each envelope size chart shows the envelope type, such as #10, 5 Baronial, A6, and the exact envelope size. You can find the standard envelope sizes in these envelope charts.
Envelope structure
Before we understand the envelope dimensions, let’s first understand its structure. Regardless of the size or type of envelope, the structure of an envelope is the same, consisting of the following components: flaps, folds, shoulders, throat, seals, and seams. Below is a diagram of the structure of an envelope. If you want to measure the length and width of the envelope, measure as shown in the picture. Generally speaking, the measurement from the bottom fold to the top fold is the height, and the measurement from left to right is the width.
Standard Envelope Sizes and Styles
Envelopes play an essential role in our lives. We use envelopes to send letters, invitations, cards, contracts, documents, etc. Therefore, it is necessary to know the standard envelope sizes and types. Here are eight standard envelope sizes and types.
#1 Commercial Envelopes
Business envelopes are the most common type of envelope used in business and office settings. They are often used to mail letters, invoices, statements, and other official documents. These envelopes come in various standard sizes, the most popular being the #10 envelope size ( 4 1/8″ x 9 1/2″). Business size envelopes typically have square flaps and business flaps for easy sealing.
Advantages of Commercial Envelopes：
The business size envelopes are the industry standard for business correspondence.
Business envelopes are ideal for mailing invoices, checks, and statements.
Business envelopes come in different flap styles, such as business flap, square flap, and wallet flap.
The #10 envelope size is the standard business envelope size.
Commercial Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| #6 1/4 | 3.5 x 6 | 89 x 152 | 3.25 x 5.75 | 83 x 146 |
| #6 3/4 | 3.625 x6.5 | 92 x 165 | 3.5 x 6.25 | 89 x159 |
| #7 | 3.75 x 6.75 | 95 x 171 | 3.5 x 6.5 | 89 x 165 |
| #7 3/4 | 3.875 x7.5 | 98 x190 | 3.75 x7.25 | 95 x184 |
| #8 5/8 | 3.625 x8.625 | 92 x219 | 3.5 x 8.375 | 89 x213 |
| #9 | 3.875 x8.875 | 98 x225 | 3.75 x 8.625 | 95 x219 |
| #10 | 4.125 x9.5 | 105 x241 | 4 x 9.25 | 102 x 235 |
| #11 | 4.5 x 10.375 | 114 x264 | 4.375 x10.125 | 111 x257 |
| #12 | 4.75 x 11 | 121 x279 | 4.625 x10.75 | 117 x273 |
| #14 | 5 x11.5 | 127 x 292 | 4.875 x11.25 | 124×286 |
#2 Baronial Envelopes
Baronial envelopes have a deep, pointed flap, often smaller than commercial envelopes. Standard Baronial envelope sizes include 4-Bar (3 5/8″ x 5 1/8″) and 5-Bar (4 1/8″ x 5 1/2″). Baronial envelopes are elegant and formal, popular in formal events, special occasions, and personal correspondence. Baronial envelope dimensions are typically used for invitations, greeting cards, announcements, and thank-you notes. Using Baronial envelopes can make a refined impression on your correspondence.
Advantages of Baronial Envelopes：
The design and pointed flap of the baronial envelopes are very sophisticated and elegant.
Baronial Envelopes are suitable for wedding invitations, greeting cards, invitations, and formal announcements.
Baronial envelopes are usually made of high-quality premium paper.
The baronial envelope dates back to the European nobility and has maintained its classical charm.
Baronial Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| 4 Baronial(A1) | 3.625×5.125 | 92×130 | 3.5×4.875 | 89×124 |
| 5 Baronial | 4.125×5.625 | 105×143 | 4×5.25 | 102×133 |
| 5 1/2 Baronial | 4.375 x5.75 | 111 x146 | 4.25 x5.5 | 108 x 140 |
| 6 Baronial | 4.75 x 6.5 | 120×165 | 4.625 x6.25 | 117 x 159 |
| 7 Baronial/Lee | 5.25 x7.25 | 133 x184 | 5.125 x7 | 130 x 178 |
#3 Square Envelopes
Square envelopes are a unique and modern envelope style with equal length and width, with standard envelope sizes ranging from 5 x 5 (inches) to 7 x 7 (inches). Square envelopes often feature a distinctive square flap and durable side seam construction, making them perfect for sending unique invitations, stylish greeting cards, and more.
Advantages of Square Envelopes：
Square envelopes have a unique look that will catch your eye.
Square envelopes are perfect for upscale events like weddings, luxury items, or corporate invitations.
Square envelopes are popular for arts and crafts.
Square envelopes have a larger print area on the closure.
Square Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| 5 square | 5×5 | 127 x127 | 4.75 x 4.75 | 121 x 121 |
| 5 1/2 square | 5.5×5.5 | 140 x140 | 5.25 x5.25 | 133 x133 |
| 6 Square | 6×6 | 152×152 | 5.75 x5.75 | 146 x 146 |
| 6 1/2 Square | 6.5 x6.5 | 165 x165 | 6.25 x6.25 | 159 x159 |
| 7 Square | 7×7 | 178 x178 | 6.75 x6.75 | 171 x 171 |
| 7 1/2 Square | 7.5 x7.5 | 191 x 191 | 7.25 x 7.25 | 184x 184 |
| 8 Square | 8×8 | 203 x203 | 7.75 x7.75 | 197 x197 |
| 8 1/2 Square | 8.5 x 8.5 | 216 x216 | 8.25 x 8.25 | 210x 210 |
#4 Booklet Envelopes
Booklet envelopes are typically rectangular and available in various sizes to accommodate different document sizes. Standard envelope sizes include 6 x 9 inches, 9 x 12 inches, and 10 x 13 inches. Booklet envelopes feature long-side flaps, allowing smooth loading and unloading of even the bulkiest documents. Booklet envelopes accommodate standard-sized sheets of paper, booklets, catalogs, or multi-page documents without folding them.
Advantages of Booklet Envelopes：
Brochure envelopes are ideal for mailing thicker documents such as brochures, catalogs, and manuals.
Brochure envelopes have flaps on the long end, making them easier to load manually.
Brochure envelopes are usually made of heavyweight paper or cardstock, which makes them very durable.
Brochure envelopes are suitable for business communications, presentations, and formal invitations.
Booklet Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| 6×9 | 6×9 | 152 x229 | 5.75 x8.75 | 146 x222 |
| 6.5 x9.5 | 6.5 x9.5 | 165 x241 | 6.25 x9.25 | 159 x235 |
| 9 x 12 | 9×12 | 229 x305 | 8.75 x11.75 | 222 x298 |
| 9.5 x 12.5 | 9.5×12.5 | 241 x318 | 9.25 x12.25 | 235 x 311 |
| 10 x 13 | 10 x13 | 254×330 | 9.75 x12.75 | 248 x324 |
#5 Catalog Envelopes
Catalog envelopes are strong and durable; catalog envelopes have a center seam, are usually rectangular, and have a large flap on the short side to ensure a secure seal. Catalog envelopes come in many large sizes, with standard envelope sizes including 9 x 12 inches and 10 x 13 inches. Catalog envelopes are an excellent choice for mailing heavyweight materials, including catalogs, large brochures, thick reports, and multiple documents.
Advantages of Catalog Envelope：
Catalog envelopes are larger and can easily fit in and out large items.
Catalog envelopes are usually made of high-quality materials and are very durable.
Catalog covers have a strong closure located on the shorter side of the cover for solid security.
Catalog envelopes are widely used in various industries, such as publishing, marketing, real estate, and law.
Catalog Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| 6×9 | 6×9 | 152 x229 | 5.75 x8.75 | 146×222 |
| 7×10 | 7×10 | 178 x254 | 6.75 x 9.75 | 171 x248 |
| 9x 12 | 9×12 | 229×305 | 8.75 x11.75 | 222×298 |
| 10 x 13 | 10 x 13 | 254×330 | 9.75 x 12.75 | 248 x324 |
| 12 x 15.5 | 12×15.5 | 305 x394 | 11.75 x 15.25 | 298 x387 |
#6 Announcement Envelopes
Announcement envelopes also known as A-Style envelopes, feature a deep square flap and side seam construction. Announcement envelopes have many sizes, with common sizes including a2 envelope size (4 3/8″ x 5 3/4″), a6 envelope size (4 3/4″ x 6 1/2″), and a7 envelope size (5 1/4″ x 7 1/4″). A-frame and Baronial envelopes can share common dimensions; for example, a 5-1/2 Baronial is the same size as an A2. A-frame envelopes are great for wedding invitations, graduation announcements, greeting cards, invitations, photos, and more.
Advantages of Announcement Envelopes：
Announcement envelopes are larger and are perfect for sending invitations, greeting cards, formal letters, etc.
Announcement envelopes can accommodate unfolded paper.
Announcement envelopes can display company branding elements such as logos.
- Announcement envelopes are unique and have a formal and elegant look.
Announcement Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| A2 | 4.375 x5.75 | 111 x146 | 4.25 x5.5 | 108 x 140 |
| A6 | 4.75 x 6.5 | 120×165 | 4.625 x6.25 | 117 x 159 |
| A7 | 5.25 x7.25 | 133 x184 | 5.125 x7 | 130 x 178 |
| A8 | 5.5 x8.125 | 140×206 | 5.375 x7.875 | 137 x200 |
| A9 | 5.75 x8.75 | 146 x222 | 5.625 x8.5 | 143 x216 |
| A10 | 6×9.5 | 152×241 | 5.875 x 9.25 | 149×235 |
#7 Remit Envelopes
Remit envelopes, also known as remittance envelopes, are special envelopes commonly used to mail payments and donations. These envelopes usually contain a pre-printed form on the flap or inside the envelope for the recipient to fill out their information, such as bill details or donation amount. Remittance envelopes come in many sizes, with 6 3/4, 9, and 10 being the most common. Organizations such as charities, banks, and utility companies often use remittance envelopes to collect payments or donations through the mail.
Advantages of Remit Envelopes：
The remittance envelope contains various information, making it very convenient to receive money.
The remittance envelope has a large flap.
The remittance envelope provides a professional and secure way to receive money.
The remittance envelope is perfect for organizations such as charities and schools.
Remit Envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| #6 ¾ Remit | 3.625 x6.5 | 92 x165 | 3.5×6.25 | 89 x159 |
| #7 ¾ Remit | 3.875 x7.5 | 98 x 190 | 3.75 x7.25 | 95 x 184 |
| #9 Remit | 3.875 x8.875 | 98 x225 | 3.75 x8.425 | 95 x219 |
| #10 Remit | 4.125 x9.5 | 105 x241 | 4×9.25 | 102 x235 |
| #11 Remit | 4.5 x10.375 | 114 x264 | 4.375 x10.125 | 111 x257 |
#8 Window envelopes
A window envelope has a transparent window and is usually made of plastic. The address and name of the recipient can be displayed directly through the window, and there is no need to print the recipient information separately on the envelope, which can save time in mailing. Window envelopes are widely used in our daily life. Enterprises, banks, and individuals can use window envelopes to send invoices, statements, or other letters.
Advantages of Window Envelopes：
- Using window envelopes can save costs.
- There is no need to print recipient information with window envelopes.
- Using window envelopes can simplify the mailing process, saving time and effort.
- The transparent window makes your mailing look professional and sophisticated.
- Window envelopes can be used for invoices, bills, statements, and general letters.
Window envelope Sizes Chart
| Envelope Type | Envelope Size(inches) | Envelope Size(mm) | Max. Enclosure Size(inches) | Max. Enclosure Size(mm) |
| #6 ¾ Window | 3.625 x6.5 | 92 x165 | 3.5×6.25 | 89 x159 |
| #9 Window | 3.875 x8.875 | 98 x 225 | 3.75 x8.625 | 95 x 219 |
| #10 Window | 4.125 x9.5 | 105 x 241 | 4×9.25 | 102 x235 |
| #11 Window | 4.5 x10.375 | 114 x264 | 4.375 x10.125 | 111 x257 |
| #12 Window | 4.75 x11 | 121 x279 | 4.625 x10.75 | 117 x 273 |
FAQ
What size envelope for a 5x7 card?
For a 5×7 card, the best-fitting envelope size is an A7 envelope. The A7 envelope measures 5.25 x 7.25 inches (133 x 184 mm), providing just enough room to fit the 5×7 card comfortably while leaving a slight margin for easy insertion and removal.
What is a standard business envelope size?
A standard business envelope is #10 envelope size, 4.125 x 9.5 inches (105 x 241 mm). This envelope size is widely used for mailing standard 8.5 x 11-inch documents folded into thirds, such as letters, invoices, and statements. The #10 envelope is the most common size used in business correspondence.
Will a #9 envelope fit inside a #10 envelope?
Yes, a #9 envelope will fit inside a #10 envelope.
A #9 envelope typically measures 3.875 x 8.875 inches (98 x 225 mm), while a #10 envelope measures 4.125 x 9.5 inches (105 x 241 mm). The small size of the #9 envelope allows it to fit comfortably inside the #10 envelope.
What are the A4 envelope dimensions?
The A4 envelope dimensions are 9 x 12.75 inches (229 x 324 mm).
What are the invitation envelope dimensions?
A7 Envelope: 5.25 x 7.25 inches (133 x 184 mm)
Fits: 5 x 7-inch invitations or cards. A7 envelope sizes are the most common for formal invitations like weddings.
A2 Envelope: 4.375 x 5.75 inches (111 x 146 mm)
Fits: 4.25 x 5.5-inch invitations or cards.
A6 Envelope: 4.75 x 6.5 inches (121 x 165 mm)
Fits: 4.5 x 6.25-inch invitations or cards
A9 Envelope: 5.75 x 8.75 inches (146 x 222 mm)
Fits: 5.5 x 8.5-inch invitations or cards
What size is an A5 envelope?
A5 envelope is also a C5 envelope, 6.38 x 9.02 inches (162 x 229 mm). The C5 envelope sizes suit invitations, greeting cards, brochures, and other medium-sized documents.
Can I have custom envelope sizes?
You can customize envelope sizes to suit your needs. For example, you can order large or small envelopes that are not standard envelope sizes. You can also customize the envelope’s color, material, flaps, seams, and more.
What size envelope can hold an A6 or pocket-sized notebook?
For an A6 Notebook:
C6 Envelope (114 mm × 162 mm or 4.5″ × 6.4″)
This is the most common envelope size for A6 items, offering enough room for a snug fit.
For a Thicker Pocket-Sized Notebook:
A6+ or Custom Envelopes:
If the notebook is thicker, you might need a slightly larger envelope like an A6+ or padded mailer designed for bulkier items.
Choosing the right envelope size often depends on the size of the item you’re mailing or storing. If you’re looking for details on standard notebook sizes to pair with your envelopes, check out Paper Notebook Sizes Explained: The Ultimate Guide for more information.
Conclusion
Envelopes come in many sizes and shapes. As a trusted stationery supplier, Honeyoung explains the standard sizes of most envelopes you might need in life, work, or business communication. Whether you need envelopes for invitations, greeting cards, or mailing letters, you can find the right one among the eight standard envelope sizes and types above.
2 Responses
The envelope size table provided in the article is very detailed, which helps me choose the appropriate envelope according to the size of the invitation.
How to better integrate envelope design with invitation letters, greeting cards, and other content?