A2 envelope: size, what fits and how to print the address

What an A2 envelope is for

The A2 is the standard envelope for small greeting cards in the US and Canada. It measures 111.1 × 146.1 mm (4⅜ × 5¾ in), just big enough for a 4¼ × 5½ in card, which is what you get when you fold a sheet of US Letter paper in half and then in half again. Most homemade greeting cards, printable thank-you notes and boxed note cards are that size, so the A2 is the envelope that's sold with them. Wedding stationers use it for RSVP cards too, often as the reply envelope tucked inside an invitation that's mailed in an A7 envelope.

Don't confuse the name with the ISO paper size A2, which is a poster sheet of 420 × 594 mm. The A envelopes (A2, A6, A7 and so on) are an American series of announcement envelopes, and their numbers have nothing to do with ISO paper sizes. If your card is in an ISO size such as A6, you need a C-series envelope instead, as the next section explains.

What fits inside an A2 envelope

Cards up to 4¼ × 5½ in fit, with just enough room around them that the card slides in without rattling about. Besides the quarter-fold card, that includes a half-letter sheet (5½ × 8½ in) folded once, and flat note cards or RSVP cards cut to 4¼ × 5½ in. A photo, check or gift card tucked inside the card is fine too, as long as nothing sticks out past its edges.

What doesn't fit catches people out more often. A 4 × 6 in photo or postcard is longer than the envelope and needs an A6 envelope, and a 5 × 7 in card needs an A7. The ISO A6 card of 105 × 148 mm, which is A4 folded in four, is the trap for anyone in the UK or Europe who orders A2 envelopes online: it's narrower than the envelope but a couple of millimeters too long, so it won't go in properly. For A6 cards, use a C6 envelope, which is made for exactly that size.

Printing the address on an A2 envelope

An A2 envelope is narrow enough for most home printers, but it's small and light, so how you feed it matters more than it does with a business envelope. Use the rear or manual feed slot if your printer has one, feed the envelope short edge first in most cases, and slide the guides in until they touch both sides, because a loose envelope drifts as it feeds and the address comes out crooked. Which way the flap should face differs between printers, so check the envelope icon by the tray and print a test on plain paper cut to the same size before you use the good envelopes.

The print button on this page opens an A2 envelope that's already laid out, with your return address top left, the recipient in the middle and the stamp corner left free. Script fonts such as Great Vibes or Dancing Script suit RSVPs and thank-you notes, and the exported PDF is exactly the envelope's size, so print it at 100% (actual size) and nothing shifts. For a whole guest list, use mail merge: import the addresses from Excel, a CSV file or a Google Sheets export and print one envelope per guest. Mail merge needs a free account; free accounts have a monthly limit, and Pro is unlimited. If your printer won't take small envelopes at all, print address labels on a sheet instead and stick them on.

Postage for an A2 envelope in the US and UK

In the US, a card in an A2 envelope is mailed as a letter, not as the more expensive large envelope, because it is well within the limits for letters: Up to 11½ × 6⅛ in, ¼ in thick, 3.5 oz. A quarter-fold card on cardstock and its envelope weigh about half an ounce together, which is under the first weight step of 1 oz, so one Forever stamp covers it. Even with a photo or a short note slipped inside, it normally stays under that ounce.

Raised decorations can cost you more than that one stamp, because USPS charges the non-machinable surcharge for envelopes that are rigid or lumpy or have clasps, string or buttons, and asks you not to put rigid objects such as coins, keys or flash drives in a letter. The pitfall that is particular to the A2 is its shape: it is only a little wider than it is tall, so it's tempting to turn it upright and write the address along the short side. Keep the address running along the long side, because USPS also charges more for envelopes that are square or vertical (taller than they are wide). If you're mailing a stack of holiday cards, the guide to mailing Christmas cards in the US covers stamps and send-by dates.

In the UK, Royal Mail counts an A2 envelope as a Letter, its smallest and cheapest format, as long as it stays within these limits: Up to 24 × 16.5 cm, 5 mm thick, 100 g. An A2 envelope is far smaller and lighter than that, so a single first or second class stamp normally covers it, and the thickness is the limit to watch. A layered handmade card with embellishments can go over it even when it doesn't look chunky, and then it becomes a Large Letter, which costs more. In both countries the post office's own scale and size gauge have the final say, so weigh anything unusual before you buy stamps for a whole batch.