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Here's help understanding envelope sizes.

Comprehensive Envelope Size Chart & Guide

The complete resource for understanding standard envelope dimensions and types

Finding the Perfect Envelope for Your Needs

Envelopes are most commonly converted from text/writing weight papers. The weight is important for many reasons: thickness represents quality and durability, but can also add to the weight of your mailing, potentially incurring additional postage costs. It's essential to determine the purpose of your project and the potential weight of the complete mailing to make the best choice.
For detailed paper weight information, be sure to visit our 'paper weight info' page & chart.

Envelope Size Chart & Detailed Descriptions

(This comprehensive chart is provided for information purposes, we do not stock all dimensions listed below)

Quick Reference: Popular Envelope Size Comparison

Finding the right envelope size doesn't have to be complicated. Here's a quick comparison of the most commonly used envelope sizes across different categories:

Category Most Popular Size Dimensions (inches) Common Use
Business No. 10 4.125 x 9.5 Standard business correspondence
Booklet 6 x 9 6 x 9 Brochures and marketing materials
Catalog 9 x 12 9 x 12 Catalogs and large documents
Square 6.5 Square 6.5 x 6.5 Wedding invitations and cards
Baronial Lee/7Bar 5.25 x 7.25 Formal invitations
Announcement A-2 4.375 x 5.75 Greeting cards and announcements

Find Your Perfect Envelope Quickly

Select a category to filter envelope types based on your needs:

Learn the anatomy of an envelope and its key components: top fold, side seam, envelope throat, seam overlap, and more. Understanding these elements will help you choose the right envelope for your specific requirements.

View the Envelope Anatomy Guide

For a visual representation of envelope sizes, check out our ENVELOPE CHART which
shows envelopes ranging from Smaller --> to --> Larger.

Business & Correspondence Envelopes

Business and Commercial Envelopes are the professional standard for office correspondence, formal letters, and everyday mailing needs. These versatile envelopes come in various sizes and flap styles to suit different requirements.

The standard #10 envelope is the most widely used business envelope in the United States. With options including Square Flap, Policy, and Commercial flap styles, the #10 has become popular for both professional and personal correspondence. Choosing a #10 envelope with a square flap can add a distinctive touch to what might otherwise be considered a conventional envelope design.

Commercial flaps provide reliable sealing for everyday use, while wallet flaps offer a larger area ideal for custom printing or branding. Side seam construction makes these envelopes perfect for machine insertion in high-volume mailing operations.

Shop for Business Envelopes

Type Size Suggested Enclosure (varies according to insert thickness)
No. 6 1/4 (#6-1/4) Commercial
No. 6 1/4 Remittance
Shop 6-1/4 Remit Now
inches: 3.5 x 6 (mm: 88.9 x 152.4) inches: 3.25 x 5.75 (mm: 82.55 x 146.05)
No. 6 3/4 (#6-3/4)
Shop 6-3/4 Commercial Envelopes Now
inches: 3.625 x 6.5 (mm: 92.075 x 165.1) inches: 3.5 x 6.25 (mm: 88.9 x 158.75)
No. 8 5/8 (#8-5/8)
Shop Check Envelopes Now
inches: 3.625 x 8.625 (mm: 92.075 x 219.075) inches: 3.5 x 8.375 (mm: 88.9 x 212.725)
No. 7 (#7)
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inches: 3.75 x 6.75 (mm: 95.25 x 171.45) inches: 3.5 x 6.5 (mm: 88.9 x 165.1)
Monarch (#7-3/4)
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inches: 3.875 x 7.5 (mm: 98.425 x 190.5) inches: 3.75 x 7.25 (mm: 95.25 x 184.15)
No. 9 (#9)
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inches: 3.875 x 8.875 (mm: 98.425 x 225.425) inches: 3.75 x 8.625 (mm: 95.25 x 219.075)
9 (policy) inches: 4 x 9 (mm: 101.6 x 228.6) inches: 3.75 x 8.5 (mm: 95.25 x 215.9)
No. 10
Shop #10 Envelopes Now
inches: 4.125 x 9.5 (mm: 104.775 x 241.3) inches: 4 x 9.25 (mm: 101.6 x 234.95)
DL (International)
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inches: 4.313 x 8.625 (mm: 109.5502 x 219.075) inches: 4.125 x 8.375 (mm: 104.775 x 212.725)
No. 11 (#11)
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inches: 4.5 x 10.375 (mm: 114.3 x 262.525) inches: 4.25 x 10.125 (mm: 107.95 x 257.175)
No. 12 (#12)
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inches: 4.75 x 11 (mm: 120.65 x 279.4) inches: 4.5 x 10.75 (mm: 114.3 x 273.05)
No. 14 (#14)
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inches: 5 x 11.5 (mm: 127 x 292.1) inches: 4.75 x 11.25 (mm: 120.65 x 285.75)
16 inches: 6 x 12 (mm: 152.4 x 304.8) inches: 5.75 x 11.75 (mm: 146.05 x 298.45)
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Booklet Envelopes

Booklet Envelopes are designed specifically for mailing booklets, brochures, annual reports, and promotional materials. Their side seam construction provides excellent durability while maintaining a professional appearance.

The open side design makes booklet envelopes ideal for automated insertion equipment, making them perfect for high-volume mailings. Their flat, clean appearance maintains a professional look for your marketing materials, while providing ample space for addressing and postal markings.

Booklet envelopes are commonly used for annual reports, marketing brochures, sales materials, magazines, catalogs, and promotional literature. Their wide variety of sizes accommodates nearly any document dimensions, from small pamphlets to full-size publications.

Type Size Suggested Enclosure (varies according to insert thickness)
3 inches: 4.75 x 6.5 (mm: 120.65 x 165.1) inches: 4.5 x 6 (mm: 114.3 x 152.4)
4 1/2 inches: 5.5 x 7.5 (mm: 139.7 x 190.5) inches: 5.25 x 7 (mm: 133.35 x 177.8)
5 inches: 5.5 x 8.125 (mm: 139.7 x 206.375) inches: 5.25 x 7.625 (mm: 133.35 x 193.675)
6 inches: 5.75 x 8.875 (mm: 146.05 x 225.425) inches: 5.5 x 8.375 (mm: 139.7 x 212.725)
No. 6 1/2 (#6-1/2) Booklet
No. 6 1/2 Booklet
Shop 6-1/2 Booklet Now
inches: 6 x 9 (mm: 152.4 x 228.6) inches: 5.75 x 8.5 (mm: 146.05 x 215.9)
6 5/8 inches: 6 x 9.5 (mm: 152.4 x 241.3) inches: 5.75 x 9 (mm: 146.05 x 228.6)
6 3/4 inches: 6.5 x 9.5 (mm: 165.1 x 241.3) inches: 6.25 x 9 (mm: 158.75 x 228.6)
7 1/4 inches: 7 x 10 (mm: 177.8 x 254) inches: 6.75 x 9.5 (mm: 171.45 x 241.3)
No. 7 1/2 (#7-1/2) Booklet
No. 7 1/2 Booklet
Shop 7-1/2 Booklet Now
inches: 7.5 x 10.5 (mm: 190.5 x 266.7) inches: 7.25 x 10 (mm: 184.15 x 254)
9 inches: 8.75 x 11.5 (mm: 222.25 x 292.1) inches: 8.5 x 11 (mm: 215.9 x 279.4)
9 1/2 (9.5 Booklet) inches: 9 x 12 (mm: 228.6 x 304.8) inches: 8.75 x 11.5 (mm: 222.25 x 292.1)
10 inches: 9.5 x 12.625 (mm: 241.3 x 320.675) inches: 9.25 x 12.125 (mm: 234.95 x 307.975)
13 (13 Booklet) inches: 10 x 13 (mm: 254 x 330.2) inches: 9.75 x 12.5 (mm: 247.65 x 317.5)
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Catalog Envelopes

Catalog Envelopes feature center seam construction, making them exceptionally durable for mailing heavy-weight materials and bulky items. Their robust design makes them perfect for shipping catalogs, large publications, and important documents that require extra protection.

The center seam provides superior strength compared to side seam construction, allowing these envelopes to handle significant weight without tearing. This makes catalog envelopes the preferred choice for sending substantial documents that need to arrive in pristine condition.

Due to their unique construction, catalog envelopes cannot be processed through automatic inserting equipment or laser printers. They are designed primarily for manual insertion of heavier materials where durability is the priority over automation compatibility.

Type Size Suggested Enclosure (varies according to insert thickness)
No. 1 (#1) Catalog
No. 1 Catalog
Shop 1 Catalog Now
inches: 6 x 9 (mm: 152.4 x 228.6) inches: 5.75 x 8.75 (mm: 146.05 x 222.25)
1 3/4 inches: 6.5 x 9.5 (mm: 165.1 x 241.3) inches: 6.25 x 9 (mm: 158.75 x 228.6)
3 inches: 7 x 10 (mm: 177.8 x 254) inches: 6.75 x 9.5 (mm: 171.45 x 241.3)
No. 6 (#6) Catalog
No. 6 Catalog
Shop 6 Catalog Now
inches: 7.5 x 10.5 (mm: 190.5 x 266.7) inches: 7.25 x 10 (mm: 184.15 x 254)
8 inches: 8.25 x 11.25 (mm: 209.55 x 285.75) inches: 8 x 10.75 (mm: 203.2 x 273.05)
9 3/4 inches: 8.75 x 11.25 (mm: 222.25 x 285.75) inches: 8.5 x 10.75 (mm: 215.9 x 273.05)
10 1/2 (10.5 Catalog) inches: 9 x 12 (mm: 228.6 x 304.8) inches: 8.75 x 11.5 (mm: 222.25 x 292.1)
12 1/2 inches: 9.5 x 12.5 (mm: 241.3 x 317.5) inches: 9.25 x 12 (mm: 234.95 x 304.8)
13 1/2 (13.5 Catalog) inches: 10 x 13 (mm: 254 x 330.2) inches: 9.75 x 12.5 (mm: 247.65 x 317.5)
14 1/2 inches: 11.5 x 14.5 (mm: 292.1 x 368.3) inches: 11.25 x 14 (mm: 285.75 x 355.6)
15 inches: 10 x 15 (mm: 254 x 381) inches: 9.75 x 14.5 (mm: 247.65 x 368.3)
15 1/2 inches: 12 x 15.5 (mm: 304.8 x 393.7) inches: 11.75 x 15 (mm: 298.45 x 381)
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Square Envelopes

Square Envelopes offer a contemporary, distinctive alternative to traditional rectangular envelopes. Their unique proportions immediately capture attention, making them perfect for wedding invitations, special announcements, greeting cards, and creative marketing materials.

Constructed with side seams and featuring a modern square flap, these envelopes combine style with practicality. Their unconventional shape stands out in a stack of mail, ensuring your message receives the attention it deserves.

Important Postal Information: Square envelopes are considered non-standard by the US Postal Service and require additional postage for mailing. Be sure to check current postal regulations when using square envelopes for your mailings.

Type Size Suggested Enclosure (varies according to insert thickness)
5 Square (5X5)
Shop 5 SQ Envelopes Now
inches: 5 x 5 (mm: 127 x 127) inches: 4.75 x 4.75 (mm: 120.65 x 120.65)
5 1/2 Square (5.5X5.5)
Shop 5.5 SQ Envelopes Now
inches: 5.5 x 5.5 (mm: 139.7 x 139.7) inches: 5.25 x 5.25 (mm: 133.35 x 133.35)
6 Square (6X6)
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inches: 6 x 6 (mm: 152.4 x 152.4) inches: 5.75 x 5.75 (mm: 146.05 x 146.05)
6 1/2 Square (6.5X6.5)
Shop 6.5 SQ Envelopes Now
inches: 6.5 x 6.5 (mm: 165.1 x 165.1) inches: 6.25 x 6.25 (mm: 158.75 x 158.75)
7 Square (7X7)
Shop 7 SQ Envelopes Now
inches: 7 x 7 (mm: 177.8 x 177.8) inches: 6.75 x 6.75 (mm: 171.45 x 171.45)
7 1/2 Square (7.5X7.5)
Shop 7.5 SQ Envelopes Now
inches: 7.5 x 7.5 (mm: 190.5 x 190.5) inches: 7.25 x 7.25 (mm: 184.15 x 184.15)
8 Square (8X8)
Shop 8 SQ Envelopes Now
inches: 8 x 8 (mm: 203.2 x 203.2) inches: 7.75 x 7.75 (mm: 196.85 x 196.85)
8 1/2 Square (8.5X8.5)
Shop 8.5 SQ Envelopes Now
inches: 8.5 x 8.5 (mm: 215.9 x 215.9) inches: 8.25 x 8.25 (mm: 209.55 x 209.55)
9 Square (9X9)
Shop 9 SQ Envelopes Now
inches: 9 x 9 (mm: 228.6 x 228.6) inches: 8.75 x 8.75 (mm: 222.25 x 222.25)
9 1/2 Square (9.5X9.5)
Shop 9.5 SQ Envelopes Now
inches: 9.5 x 9.5 (mm: 241.3 x 241.3) inches: 9.25 x 9.25 (mm: 234.95 x 234.95)
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Baronial Envelopes

Baronial Envelopes feature an elegant design with a deep pointed flap and diagonal seams. Their classic, sophisticated appearance makes them the traditional choice for formal business announcements, wedding invitations, and high-end greeting cards.

The distinctive pointed flap of baronial envelopes adds a touch of formality and elegance that immediately signals the importance of the enclosed document. This traditional design has been associated with formal correspondence for generations, conveying a sense of importance and refinement.

Due to their specialized construction, baronial envelopes are not recommended for machine insertion. Their design prioritizes aesthetics and tradition over automation compatibility, making them best suited for hand-insertion of important formal documents.

Shop for Baronial Style Envelopes

** This size is too small to mail.
Type Size Suggested Enclosure (varies according to insert thickness)
Professional ** inches: 2.125 x 3.625 (mm: 53.975 x 92.075) inches: 2 x 3.5 (mm: 50.8 x 88.9)
#16 (Mrs.)** inches: 2.375 x 3.375 (mm: 60.325 x 85.725) inches: 2.25 x 3.125 (mm: 57.15 x 79.375)
#17 (Mr. & Mrs.)** inches: 2.6875 x 3.6875 (mm: 68.2625 x 93.6625) inches: 2.5625 x 3.5625 (mm: 65.0875 x 90.4875)
Gladstone** inches: 3.563 x 5.562 (mm: 90.5002 x 141.2748) inches: 3.375 x 5.375 (mm: 85.725 x 136.525)
4-Bar (or A1) inches: 3.625 x 5.125 (mm: 92.075 x 130.175) inches: 3.5 x 4.875 (mm: 88.9 x 123.825)
5-Bar inches: 4.125 x 5.625 (mm: 104.775 x 142.875) inches: 4 x 5.25 (mm: 101.6 x 133.35)
5 1/2-Bar inches: 4.375 x 5.75 (mm: 111.125 x 146.05) inches: 4.25 x 5.5 (mm: 107.95 x 139.7)
6-Bar inches: 4.75 x 6.5 (mm: 120.65 x 165.1) inches: 4.625 x 6.25 (mm: 117.475 x 158.75)
Lee inches: 5.25 x 7.25 (mm: 133.35 x 184.15) inches: 5.125 x 7 (mm: 130.175 x 177.8)
Linwood/Monona Inside inches: 5.25 x 7.5 (mm: 133.35 x 190.5) inches: 5 x 7.25 (mm: 127 x 184.15)
Monona Outside inches: 5.5 x 7.75 (mm: 139.7 x 196.85) inches: 5.25 x 7.5 (mm: 133.35 x 190.5)
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Announcement Envelopes

Announcement Envelopes, also known as A-style envelopes, are a versatile and popular choice for greeting cards, invitations, photographs, small booklets, and a wide range of personal and professional communications. Their clean, contemporary design features side seam construction and a modern square flap.

A-style envelopes and Baronial envelopes sometimes share common dimensions - for example, the 5-1/2 Bar is the same size as the A2 envelope. The primary differences are in the flap style and side seam construction. If these design elements aren't critical for your project, you may want to consider which envelope type offers the most solutions for your specific needs.

Announcement envelopes are particularly popular for greeting cards, wedding invitations, thank you notes, photos, and small marketing materials. Their clean, consistent appearance and compatibility with standard card sizes make them a practical choice for both personal and business use.

Type Size Suggested Enclosure (varies according to insert thickness)
A-2
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inches: 4.375 x 5.75 (mm: 111.125 x 146.05) inches: 4.25 x 5.5 (mm: 107.95 x 139.7)
A-6
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inches: 4.75 x 6.5 (mm: 120.65 x 165.1) inches: 4.625 x 6.25 (mm: 117.475 x 158.75)
A-7
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inches: 5.25 x 7.25 (mm: 133.35 x 184.15) inches: 5.125 x 7 (mm: 130.175 x 177.8)
A-8
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inches: 5.5 x 8.125 (mm: 139.7 x 206.375) inches: 5.375 x 7.875 (mm: 136.525 x 200.025)
A-9
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inches: 5.75 x 8.75 (mm: 146.05 x 222.25) inches: 5.5 x 8.5 (mm: 139.7 x 215.9)
A-10
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inches: 6 x 9.5 (mm: 152.4 x 241.3) inches: 5.875 x 9.25 (mm: 149.225 x 234.95)
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International Envelope Standards

When corresponding internationally, it's important to understand that envelope standards vary around the world. Here's a quick guide to some common international envelope sizes:

Standard Size Common Use Region
C4 inches: 9 x 12.75 (mm: 229 x 324) Full A4 documents without folding Europe, Asia, International
C5 inches: 6.4 x 9 (mm: 162 x 229) A4 documents folded once Europe, Asia, International
C6 inches: 4.5 x 6.4 (mm: 114 x 162) A4 documents folded twice Europe, Asia, International
DL inches: 4.33 x 8.66 (mm: 110 x 220) Standard business letter (A4 folded three times) Europe, Asia, International
B4 inches: 9.84 x 13.9 (mm: 250 x 353) Large documents and catalogs Japan, Asia

When mailing internationally, be sure to check postal regulations for the destination country, as requirements can vary significantly from U.S. standards.

Eco-Friendly Envelope Options

As environmental concerns become increasingly important, many businesses and individuals are seeking more sustainable envelope options. Here are some eco-friendly alternatives to consider:

  • Recycled Paper Envelopes: Made from post-consumer waste, these offer the same quality and performance as traditional envelopes while reducing environmental impact.
  • FSC-Certified Envelopes: Forest Stewardship Council certification ensures that paper products come from responsibly managed forests.
  • Biodegradable Envelopes: These are designed to break down naturally in landfill conditions, reducing long-term waste.
  • Window Envelopes with Biodegradable Film: Traditional plastic windows can be replaced with biodegradable alternatives.
  • Minimalist Envelopes: Designs that use less paper while maintaining functionality help reduce resource consumption.

When ordering envelopes, look for recycled content percentages and environmental certifications to make the most sustainable choice for your mailing needs.

Frequently Asked Questions About Envelopes

What's the difference between a commercial flap and a square flap?
Commercial flaps have a pointed, triangular shape that's traditionally used for business correspondence. Square flaps have a straight edge that creates a more modern, distinctive look. Commercial flaps are typically better for machine insertion, while square flaps are often chosen for their aesthetic appeal.
Why do square envelopes require additional postage?
The U.S. Postal Service classifies square envelopes as "non-machinable" because they can't be processed through standard automated sorting equipment. This requires manual sorting, which is why they incur additional postage costs despite potentially weighing the same as standard envelopes.
What envelope size should I use for wedding invitations?
Popular sizes for wedding invitations include A7 (5.25" x 7.25"), A8 (5.5" x 8.125"), and 5.5" or 6" square envelopes. The right size depends on your invitation design, whether you're including response cards and additional information, and your aesthetic preferences. Remember that square envelopes require additional postage.
What's the difference between booklet and catalog envelopes?
Booklet and catalog envelopes are both used for mailing documents, but they differ in construction and how they open. Booklet envelopes open on the long edge and have side seams, making them compatible with automated insertion equipment—ideal for letters, brochures, and forms. Catalog envelopes open on the short edge and feature center seams, providing extra strength for bulkier or heavier contents, though they typically require manual insertion.
How should I address an envelope for international mailing?
For international mail, place the recipient's name on the first line, followed by their street address or post office box on the second line. The third line should contain the city, province/state, and postal code. The destination country should appear alone on the final line, written in all capital letters. Always include your return address in the upper left corner.

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