What Size Are Greeting Cards? A Complete Sizing Guide

Greeting cards come in a handful of standard sizes that the printing and stationery industries have used for decades. Each size pairs with a specific envelope, and each works best for certain types of messages.

A2 cards, 4.25" x 5.5" folded, are the smallest standard size. The flat sheet measures 8.5" x 5.5" before folding, and they fit A2 envelopes (4.375" x 5.75"). They suit short thank-you notes, RSVP cards, and simple holiday greetings, and their smaller footprint means less paper, which can lower printing costs in bulk. If you are creating flat bridal shower invites or response cards, A2 is a solid pick.

A6 cards, 4.75" x 6.5" folded, sit between A2 and A7. The flat sheet is 9.5" x 6.5" and fits an A6 envelope (4.875" x 6.625"). Photographers love A6 for photo cards because the proportions feel balanced, and it is a popular choice for save-the-date cards and business holiday greetings.

Square cards stand out in a mailbox full of rectangular envelopes. The two most common square sizes are 5" x 5" and 6" x 6" folded, with flat sheets of 10" x 5" and 12" x 6". They have a modern, design-forward feel that suits art prints, minimalist holiday cards, and brands that want something different. One thing to keep in mind is that square envelopes often require extra postage because USPS classifies them as non-machinable.

Oversized cards measure 5.5" x 8.5" or larger folded. The flat sheet for a 5.5" x 8.5" card is 11" x 8.5", which is a standard letter-size sheet folded in half. These big cards make a statement for milestone birthdays, grand openings, or VIP client appreciation.

The trade-off with oversized cards is postage. Anything over 6.125" x 11.5" or thicker than 0.25" gets classified as a parcel by USPS, which means a lot higher mailing costs. If you are learning how to make envelopes for custom sizes, factor in those postal requirements early.

The best size depends on three things: your message, your design, and your mailing budget.

Match the size to your content. Short messages and simple designs work on A2 cards, and you do not need a 5" x 7" card for "thanks for your order." Longer messages, multiple photos, or detailed illustrations need A7 or larger, and if you are including a gift card holder or pocket, go oversized.

Match the size to the occasion. Wedding invitations typically use A7, thank-you notes lean toward A2 or A6, and holiday cards from businesses almost always go 5" x 7" because it feels big without being excessive. For related projects like brochures and flyers, our guides on how to fold a brochure and how to make flyers use sizing principles that overlap across print formats.

Match the size to your budget. Smaller cards use less paper and fit in smaller envelopes, so across a 500-card run the difference between A2 and A7 adds up in both printing and postage. Square cards look great but cost more to mail, so run the numbers before committing.

Getting the size wrong on a greeting card order wastes money and time. Here are the errors 4OVER4.COM sees most often.

Designing at the folded size instead of the flat size. A 5" x 7" greeting card needs a 10" x 7" file. Submitting a 5" x 7" file gives you a card half the size you wanted.

Forgetting bleed. If your background color or image goes to the edge, you need 0.125" bleed on every side, or you will see thin white strips along the trim edges.

Ignoring envelope compatibility. Custom sizes sound fun until you cannot find an envelope that fits, so stick to standard dimensions unless you are ordering custom envelopes too.

Not checking postage before printing. Square and oversized cards cost more to mail. Across 300 holiday cards, a non-machinable surcharge can add over $130 to your mailing budget, so know what size greeting cards require extra postage before you commit to a design. For complementary print products, learn how to make custom magnets or browse the full guide hub. 4OVER4.COM also runs a pre-flight file check that catches dimension and bleed errors before your cards go to press.