Corporate Envelope Size Guide — Standard Business Envelope Dimensions Explained
Choosing the right corporate envelope size is more than a matter of dimensions — it affects postage costs, mailing efficiency, and how professional your correspondence looks. This guide covers every standard business envelope size you need to know, from the everyday #10 envelope to large catalog mailers.
Commercial Business Envelopes — The #10 Family
These are the envelopes you see in offices every day. The #10 envelope (4⅛” × 9½”) is the worldwide standard for business correspondence, designed to hold a letter-size sheet folded in thirds.
| Size | Dimensions (inches) | Typical Use |
|---|---|---|
| #6¾ | 3⅝” × 6½” | Personal correspondence, small checks |
| #9 | 3⅞” × 8⅞” | Return envelopes (fits inside #10) |
| #10 | 4⅛” × 9½” | Standard business mail — invoices, statements, letters |
| #11 | 4½” × 10⅜” | Larger business correspondence |
| #14 | 5″ × 11½” | Legal documents, unfolded letter-size sheets |
Announcement Envelopes — The A-Series
The A-series (announcement envelopes) are square-flapped envelopes used for invitations, greeting cards, and social stationery. The most popular is A7, which perfectly fits a 5×7″ invitation card.
| Size | Dimensions (inches) | Fits Card Size | Best For |
|---|---|---|---|
| A2 | 4⅜” × 5¾” | 4¼” × 5½” | RSVPs, gift notes, thank-you cards |
| A6 | 4¾” × 6½” | 4½” × 6¼” | Invitations, save-the-dates |
| A7 | 5¼” × 7¼” | 5″ × 7″ | Wedding invitations — most popular |
| A9 | 5¾” × 8¾” | 5½” × 8½” | Formal announcements, large invitations |
| A10 | 6″ × 9½” | 5¾” × 9¼” | Oversized announcements, certificates |
Catalog & Booklet Envelopes
Designed for mailing flat, larger materials that shouldn’t be folded. Custom catalog envelopes come in open-side and open-end configurations — open-side opens on the shorter dimension, open-end on the longer.
| Size | Dimensions (inches) | Fits | Best For |
|---|---|---|---|
| 6″ × 9″ | 6″ × 9″ | A5 booklets, tri-fold brochures | Marketing mailers, small catalogs |
| 9″ × 12″ | 9″ × 12″ | 8½” × 11″ sheets flat | Catalogs, annual reports, legal docs |
| 10″ × 13″ | 10″ × 13″ | Oversized materials | Large catalogs, thick documents |
Square & Specialty Sizes
Square envelopes make a distinctive impression — they stand out in a stack of rectangular mail and are increasingly popular for event invitations and brand marketing. Specialty sizes like baronial and coin envelopes serve specific niche purposes.
| Style | Dimensions (inches) | Best For |
|---|---|---|
| Square 5×5 | 5″ × 5″ | Party invitations, events, greeting cards |
| Square 6×6 | 6″ × 6″ | Formal invitations, photography mailers |
| Baronial | Various (pointed flap) | Formal invitations, social stationery |
| Coin (#3–#7) | 2½×4″ to 4×7″ | Donation envelopes, payment remittance |
Custom Envelope Sizes — When Standard Doesn’t Fit
If your insert doesn’t match any standard envelope size — or if you’re designing packaging that needs a unique format — custom envelope manufacturing is the answer. We produce envelopes in any dimension with custom die-cut windows, specialty papers, and your choice of printing and finishes.
Custom sizes typically require a minimum order of 2,000 pieces to cover die fabrication costs. For standard-size envelopes with custom printing, MOQ drops to 1,000 pieces.
Need a custom envelope size? We manufacture to your exact dimensions.
Any size, any paper, any printing — factory direct with 24-hour quotes.