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Aug 19 2026

What Size Envelope Do I Need? A Guide to Common Business Envelope Sizes

What Size Envelope Do I Need?

Choosing the right envelope size is important for protecting your documents and creating a professional appearance. Whether you are mailing invoices, letters, brochures, or promotional materials, using the correct envelope helps ensure your mail arrives in good condition and meets postal requirements.

Businesses use many different envelope sizes depending on the type of document being mailed. Understanding the most common envelope sizes can help you choose the best option for your needs.

#10 Envelopes

The #10 envelope is the most common business envelope. It measures 4 1/8" x 9 1/2" and is designed to hold a standard 8 1/2" x 11" sheet of paper folded into thirds. #10 envelopes are commonly used for:

  1. Business letters
  2. Invoices
  3. Statements
  4. Checks
  5. General correspondence

Many businesses choose #10 window envelopes for invoices and statements because the recipient's address printed on the document shows through the window.

9" x 12" Envelopes

A 9" x 12" envelope is used when documents should remain flat and unfolded.

These envelopes are commonly used for:

  1. Contracts
  2. Legal documents
  3. Reports
  4. Presentation materials
  5. Certificates

If you want your documents to arrive without fold lines, a 9" x 12" envelope is often the best choice.

10" x 13" Envelopes

A 10" x 13" envelope provides additional room for larger documents or thicker packets.

Many businesses use this size for:

  1. Catalogs
  2. Multiple-page reports
  3. Employee paperwork
  4. Marketing materials
  5. Booklets

This size is popular for offices that regularly mail large document packages.

A-Style Envelopes

A-style envelopes are commonly used for invitations, greeting cards, announcements, and promotional mailings.

They are available in several sizes and are often selected when appearance is an important part of the mailing.

Businesses frequently use A-style envelopes for:

  1. Invitations
  2. Holiday cards
  3. Thank-you cards
  4. Special announcements

Should You Choose Window or Regular Envelopes?

After selecting the correct size, you will also need to decide between window envelopes and regular envelopes.

Window envelopes work well for invoices, statements, and payroll checks because the address is printed directly on the document inside.

Regular envelopes provide more flexibility and are ideal for letters, marketing materials, brochures, and everyday business correspondence.

Choosing the right style depends on how your business prepares and mails documents.

Custom Printed Envelopes

No matter what size envelope you choose, custom printing helps create a professional image for your business. Printing your company logo, return address, and brand colors on your envelopes makes your mail easier to recognize and reinforces your company's identity.

Custom envelopes also save time by eliminating the need for return address labels or stamps.

Need Help Choosing the Right Envelope?

Summit Printing offers custom window envelopes, regular business envelopes, and mailing envelopes in a variety of sizes for businesses throughout Salt Lake City and the Wasatch Front.

Whether you need #10 envelopes for invoices or larger envelopes for reports and marketing materials, our team can help you choose the right envelope for your business. With fast turnaround times, professional-quality printing, and free local delivery, Summit Printing makes ordering custom envelopes simple and convenient.

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