Envelope size chart
Use one chart for office envelopes, RSVP sets, and flat document mailers.
The common home and office mail format for folded Letter sheets.
Usually paired with 5 x 7 cards and event invites.
Good when folding the insert would look sloppy or risky.
Quick check
What to check first
If the insert folds, think about the finished fold first. If the insert must stay flat, jump straight to the larger booklet and catalog envelopes instead of forcing the job into a business size.
- A7 is the usual starting point for 5 x 7 cards, but thicker card stock can push you toward the next size up.
- A #10 envelope is the workhorse for letters, invoices, and tri-fold office documents.
- Catalog envelopes make life easier when the contents should stay flat instead of creased.
Common envelope sizes (in / mm)
| Size name | Common name | Item size | Shape | Best use |
|---|---|---|---|---|
| #6 3/4 | Policy envelope | 3.625 x 6.5 in (92 x 165 mm) | Envelope | insurance notices and compact mail |
| #9 | Reply envelope | 3.875 x 8.875 in (98 x 225 mm) | Envelope | return mail inserts |
| #10 | Business envelope | 4.125 x 9.5 in (105 x 241 mm) | Envelope | letters, invoices, folded Letter sheets |
| A2 | Announcement envelope | 4.375 x 5.75 in (111 x 146 mm) | Envelope | RSVP cards and short notes |
| A6 | Announcement envelope | 4.75 x 6.5 in (121 x 165 mm) | Envelope | photos and invitations |
| A7 | Invitation envelope | 5.25 x 7.25 in (133 x 184 mm) | Envelope | 5 x 7 cards |
| A9 | Large invitation envelope | 5.75 x 8.75 in (146 x 222 mm) | Envelope | half-sheet cards and flat mailers |
| 6 x 9 | Booklet envelope | 6 x 9 in (152 x 229 mm) | Envelope | booklets, folded kits, manuals |
| 9 x 12 | Catalog envelope | 9 x 12 in (229 x 305 mm) | Envelope | flat documents and presentation sheets |
| 10 x 13 | Catalog envelope | 10 x 13 in (254 x 330 mm) | Envelope | larger packets and document sets |
Flat mailers and invitation envelopes solve different problems. Card fit, insert thickness, and postal handling matter more than the name printed on the box.
Common questions
What envelope fits a 5 x 7 card?
A7 is the usual answer. If the card is thick, layered, or wrapped, print a proof and test it because real bulk changes the fit.
Should a brochure go in a #10 or a 9 x 12 envelope?
Use a #10 if folding the brochure is acceptable. Use 9 x 12 when the piece should stay flat and present cleanly.
Do catalog and booklet envelopes mean the same thing?
People use the names loosely. The safer move is to compare the actual width, height, and flap style instead of trusting the label alone.