A7 envelope size: the 5×7 envelope

Why A7 is the 5×7 envelope

When a shop sells a "5×7 envelope", what you get is almost always an A7. The name describes the card that goes inside rather than the envelope, which is why the envelope itself is a little larger in both directions. A 5×7 in card sits in it with about ⅛ in of room on each side, so it slides in and out without catching its corners but doesn't shift around on its way through the mail. That margin is also why it pays to check a listing that gives the envelope's outside size as exactly 5 × 7 in before you order, because an envelope that size is too small for a 5×7 card.

A7 is the most common invitation envelope size in the US, and it's the one that comes with most blank 5×7 cards and printed invitation sets. You'll find it on wedding invitations, save-the-dates, holiday cards, birth announcements and thank-you cards. If your card is smaller, such as a folded note card or a separate RSVP card, it will slide around in an A7, and the A2 envelope made for those smaller cards is the better fit.

What fits inside, and which flap to choose

Besides a flat or folded 5×7 card, an A7 takes a 5×7 photo print, a sheet of Letter paper folded in four, or an A4 sheet folded in four. An A5 card won't go in, because it's wider than the envelope's short side, and neither will Letter paper folded once. For a wedding suite, the usual stack of a 5×7 invitation, a smaller RSVP card in its own envelope and a details card still fits, but check that the flap closes flat over the whole stack before you order.

Most A7 envelopes come with one of two flaps. A Euro flap is deep and comes to a soft point, which gives the traditional look for wedding invitations. A square flap has a straight edge and a cleaner, more modern look, and because it's shallower it leaves more of the back free for a return address. Either style can have a liner, a sheet of patterned paper glued inside the envelope and flap, which looks good when the envelope is opened but makes it slightly heavier and stiffer.

Printing the address on an A7 envelope at home

Because an A7 is much narrower than a sheet of Letter paper, most home printers take it, but how you load it decides whether the address comes out straight. Most printers feed envelopes short edge first through the rear or manual slot, flap closed, and the small envelope icon on the tray shows which side faces up. Choose the A7 size both in the editor and in your printer's print dialog, then print one copy on plain paper and hold an envelope behind it against a window to check the position before you use your good stock.

The A7 size opens in the editor as a ready template, with your return address top left, the recipient in the middle and the stamp corner left free. You can move and restyle every block, for example centering the guest's name and making it larger, and then print directly or export a PDF exactly the size of the envelope. Lined and heavy cotton envelopes are the ones most likely to jam, so feed them one at a time, or put the addresses on clear labels if your printer refuses them. For a whole guest list you can import the addresses from a spreadsheet and print one envelope per guest, which needs a free account.

How an A7 envelope counts for postage

In the US an A7 envelope counts as a letter, because its size and shape fall within the Postal Service's letter dimensions. A single 5×7 card, even with a liner, usually stays within the weight one letter stamp covers. What changes that is what you add: a full invitation suite can tip it into the next weight step, and a wax seal, ribbon or brooch makes the envelope rigid or lumpy, so it's treated as nonmachinable and costs extra. If the stack or an embellishment, such as a brooch or a thick pocket-fold suite, makes the envelope thicker than USPS allows for a letter, it stops being a letter altogether: it's priced as a large envelope (a flat), which costs more than a letter with the surcharge, or as a package if it's also rigid or uneven, which costs far more.

In the UK the same envelope fits within Royal Mail's Letter size, so a thin card goes as a Letter, while a thick one, such as a padded card or a card with a 3D topper, becomes a Large Letter. Square envelopes are a popular alternative for invitations, but in the US their shape alone costs extra, so read about square envelope sizes before switching. Whatever you send, assemble one complete envelope and have it weighed at the post office before you buy stamps for the whole list.