A7 Envelope Size: The Standard for Wedding Invitations
An A7 envelope measures 5.25" × 7.25" and fits standard 5×7 invitations. The default envelope for wedding invitations, photo cards, and formal announcements.
| Envelope Specifications | |
|---|---|
| Dimensions (inches) | 5.25" × 7.25" |
| Dimensions (mm) | 133.4mm × 184.2mm |
| Weight Limit | 3.5 |
| USPS Postage Class | First-Class letter |
| Primary Uses |
|
The A7 envelope measures 5.25 inches high by 7.25 inches long and is, by a wide margin, the most popular envelope size for wedding invitations in the United States.
The proportions exist to fit a 5 by 7 inch invitation card with about a quarter-inch margin on each side — the same 5 by 7 dimensions used for standard photo prints, formal announcements, and most premium greeting cards.
This page covers the exact dimensions, why A7 became the wedding-industry standard, USPS postage and machinability, and how the A7 compares to the smaller A6 and larger A9.
When to use an A7 envelope
Wedding invitations
The A7 is the default. Couples ordering wedding invitations through stationers or online services almost always receive 5 by 7 inch invitation cards paired with A7 envelopes — typically two of them, one outer and one inner addressing envelope for formal weddings. The size signals formal, the proportions look balanced, and the dimensions fit cleanly within USPS letter-rate rules.
Formal announcements
Engagement announcements, graduation announcements, and milestone announcements (anniversaries, retirements, births of significant family events) are commonly printed at 5 by 7 and mailed in A7 envelopes.
Holiday photo cards
The 5 by 7 photo card is the dominant holiday format, and the A7 is its envelope. December is by volume the busiest month for A7 envelopes by a wide margin.
Photography prints
Photographers shipping 5 by 7 prints to clients use A7 envelopes — often with a rigid backer to prevent bending in transit. Note that adding rigid backers can disqualify the piece from machinable rates.
When to choose a different size
For smaller cards (4.5 by 6.25), use A6. For larger formal invitations or programs, step up to A9. For a less formal, business-feeling mailing, a #10 reads differently and is often a better fit.
A7 envelope postage and USPS rules
An A7 envelope falls inside USPS letter-size limits and qualifies for First-Class letter rates — but watch the surcharge triggers carefully on invitation mailings.
2026 First-Class postage for an A7 envelope
- 1 ounce, Forever stamp: $0.78
- 1 ounce, metered postage: $0.74
- Each additional ounce, up to 3.5 ounces: $0.29
The A7's aspect ratio (length divided by height) is 1.38, comfortably inside the USPS machinable range of 1.3 to 2.5.
Wedding invitation surcharge risk
Formal wedding invitations are notorious for triggering the $0.44 nonmachinable surcharge per piece. Common culprits:
- Multiple inserts — invitation, RSVP card, RSVP envelope, reception card, accommodations card, and tissue paper add up to over 1 ounce surprisingly fast
- Heavy cardstock and embellishments — letterpress, foil stamping, and laser-cut details add weight and rigidity
- Wax seals, ribbon ties, and embossed details — anything that creates uneven thickness or rigidity
- Outer plus inner envelope sets — formal weddings double up, doubling envelope weight
If you're sending wedding invitations, weigh a fully assembled sample at the post office before printing postage on the entire run. The cost difference between letter rate and the nonmachinable rate, multiplied by 200 invitations, is real money.
Last verified: May 2026. Source: USPS Domestic Mail Manual 201.
Sean is a USPS-certified Mailpiece Design Professional (MDP) with 25+ years of experience producing compliant direct mail campaigns for Hudson Valley businesses. He has processed over 2.3 million mail pieces through the USPS Business Mail Entry Unit in New Paltz, NY since 1998.
Frequently Asked Questions
What are the dimensions of an A7 envelope?
An A7 envelope measures 5.25 inches high by 7.25 inches long (133.4 by 184.2 millimeters). It fits 5 by 7 inch invitation cards with about a quarter-inch margin on each side.
Will a 5 by 7 invitation fit in an A7 envelope?
Yes. The A7 is sized specifically for 5 by 7 inch cards, which is the standard wedding invitation size in the United States.
Why are wedding invitations sent in A7 envelopes?
The A7 became the wedding standard because 5 by 7 inch invitation cards are the dominant format in the stationery industry, and the A7 fits them with appropriate margin. The proportions read formal, and the size sits within USPS letter-rate limits.
How much does it cost to mail an A7 wedding invitation?
Letter rate starts at $0.78 in 2026, but most wedding invitations exceed 1 ounce due to multiple inserts, heavy cardstock, and embellishments — adding $0.29 per additional ounce. Many invitations also trigger the $0.44 nonmachinable surcharge for thickness or rigidity. Weigh a complete sample at the post office before printing postage.
What's the difference between A6 and A7 envelopes?
An A6 (4.75" × 6.5") is smaller and fits 4.5 by 6.25 inch cards. An A7 (5.25" × 7.25") is larger and fits 5 by 7 inch cards. A6 is typical for save-the-dates and shower invitations; A7 is typical for formal wedding invitations.
Not sure this is the right size?
Compare all standard envelope sizes side-by-side, then call us. We help Hudson Valley businesses choose, print, and mail the right format every day.
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