Free Reference · Envelopes & Mail
Envelope Size Chart: Standard Sizes
& What Fits Inside
Envelope names like "#10" or "A7" don't mean much until you know what they actually hold. Here's
every common size, in inches, matched to the paper or card it's built for.
Commercial envelope sizes
The numbered sizes used for everyday business mail.
| Size | Dimensions | Holds |
|---|---|---|
| #6¾ | 3.625 × 6.5 in | Personal letters, small statements |
| #9 | 3.875 × 8.875 in | Return/reply envelope for a #10 |
| #10 | 4.125 × 9.5 in | Letter paper folded in thirds, the standard business envelope |
| #11 | 4.5 × 10.375 in | Legal-size documents folded in thirds |
| 6 × 9 in | 6 × 9 in | Letter paper folded in half, small booklets |
| 9 × 12 in | 9 × 12 in | Unfolded letter paper |
A-series envelope sizes (cards & invitations)
| Size | Dimensions | Holds |
|---|---|---|
| A2 | 4.375 × 5.75 in | Small note cards, RSVP cards |
| A6 | 4.75 × 6.5 in | 4×6 in postcards and photo prints |
| A7 | 5.25 × 7.25 in | 5×7 in invitations, the standard for wedding invites |
| A9 | 5.75 × 8.75 in | Large invitations, formal announcements |
Manila & catalog envelope sizes
| Size | Dimensions | Holds |
|---|---|---|
| Small manila | 6 × 9 in | Booklets, small document sets |
| Standard manila | 9 × 12 in | Unfolded letter paper, resumes |
| Large manila | 10 × 13 in | Slightly oversized documents, thicker bundles |
The #10-and-A7 mix-up almost everyone makes once
The naming really is the whole problem: a #10 and an A7 both sound like arbitrary codes until you've actually stuffed one wrong. #10 is the everyday office envelope, sized for a standard letter folded twice. A7 is the wedding-invitation size, built for a flat 5x7 card, no folding involved. Order the wrong one and you'll either be jamming a folded letter into a card envelope or watching a 5x7 invite swim around inside a business envelope built for something a third its size.
If you're printing custom envelopes rather than just buying blanks, work backward from what's going inside, pick the card or paper size first, then choose the smallest envelope on this chart that fits it with a little room to spare.
Envelope size FAQs
What size envelope fits standard letter paper?
A #10 envelope (4.125 × 9.5 in) fits an 8.5 × 11 in letter folded in thirds. For a letter folded in half, use 6 × 9 in instead.
What is an A7 envelope used for?
A7 (5.25 × 7.25 in) is the standard for 5x7 in invitations and greeting cards, the most common size for wedding invitations.
What is the difference between A-series and commercial envelope sizes?
A-series envelopes are sized for cards and invitations. Commercial envelopes are numbered (#10, #9, #6) and sized for business mail like letters and invoices.
What size is a manila envelope?
Common sizes are 9 × 12 in (holds unfolded letter paper) and 10 × 13 in (slightly larger documents or a few extra sheets).
Do I need extra room in an envelope for my paper to fit?
Yes, standard sizes build in a small margin on purpose. A snug fit makes stuffing hard and can tear the paper.
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