How to Pick the Right Greeting Card Size and Format for Mailing

Quick answer

For most mailed greetings, pick an A2 note card (4.25 x 5.5 inches) when you want a short message, or an A7 greeting card (5 x 7 inches) when you want room to write. Both fit standard envelopes and a standard first-class stamp, but thicker cardstock and heavier enclosures can push you into extra postage. If you are unsure, start with A2 for notes and A7 for cards.

A card that will not fit its envelope or costs extra to mail is a small frustration you can avoid with two decisions: format and size. This guide walks through the common greeting card sizes, how they relate to envelope sizes, and what cardstock thickness does to postage and durability.

You will also get a simple note card vs greeting card rule and practical mailing checks, so you can buy or make cards that arrive flat, clean, and on time.

The two formats: note card vs greeting card

A note card is usually a flat or lightly folded card with a small writing area, often used for quick thanks, lunch invitations, or enclosure notes. A greeting card is typically a folded card with a larger blank inside, used for birthdays, holidays, and longer messages. The format changes how much you can write, how the card stands on a shelf, and how it feels in the hand.

If your message is under about 50 words, a note card keeps things tidy and costs less to mail. If you plan to write several paragraphs or include a small photo, choose a greeting card so the fold protects the contents and gives you space.

• Note cards: quick notes, thank-yous, enclosure cards, gift tags.
• Greeting cards: birthdays, holidays, sympathy, and any message over a few sentences.
• Folded cards hide handwriting smudges better than flat cards when stacked in an envelope.

Common greeting card sizes and envelope matches

The most common greeting card sizes are A2 (4.25 x 5.5 inches), A6 (4.625 x 6.25 inches), and A7 (5 x 7 inches). A2 and A6 usually take an A2 or A6 envelope, while A7 takes an A7 envelope. These are the sizes most cardstock and envelope packs are built around, so matching them is straightforward.

If you are buying cards separately from envelopes, check the envelope's stated size rather than the card's nickname. A card labeled 5 x 7 will not fit a 4.75 x 6.5 envelope, and a square card often needs extra postage because it is not machinable at the standard rate. When in doubt, buy the card and envelope as a set.

• A2: 4.25 x 5.5 inches, best for short notes and small enclosures.
• A6: 4.625 x 6.25 inches, a middle size that fits many photo prints.
• A7: 5 x 7 inches, best for longer messages and 5 x 7 photos.
• Square cards: charming, but often require extra postage.

Cardstock thickness: what it changes

Cardstock thickness is measured in points or pounds, and it affects how the card feels, how it folds, and how it travels. A light cardstock (around 65-80 lb cover) folds easily and mails at the standard rate, but it can bend in sorting machines. A heavier cardstock (100 lb cover or more) feels substantial and resists bending, but it may need a non-machinable stamp if the envelope becomes rigid or bulky.

For mailing, choose a mid-weight cardstock that holds a crease without cracking. If you add thick embellishments, wax seals, or multiple inserts, weigh the finished envelope or take it to a postal counter to confirm the rate. The card's thickness alone rarely causes a problem; the total envelope weight and stiffness do.

• 65-80 lb cover: light, folds easily, standard postage.
• 80-100 lb cover: good balance for mailed cards.
• 100 lb+ cover: premium feel, check postage if the envelope is stiff.
• Avoid thick embellishments if you want to use a standard stamp.

Mailing checks before you send

Before you mail a batch of cards, test one envelope. Address it, seal it, and check that the flap stays down. If the envelope bulges, the card may jam in sorting equipment. Write the address clearly and leave space for the stamp and return address. If you are mailing internationally, check the destination's size and weight limits, because a card that is standard in one country may not be in another.

For small notes, a note card in an A2 envelope is the safest bet. For anything thicker or more than a few pages, use a padded mailer or a rigid photo mailer instead of a standard envelope. That keeps the card flat and avoids extra postage surprises.

• Test one card and envelope before mailing the whole set.
• Keep the envelope flat; bulges can cause non-machinable surcharges.
• Use a rigid mailer for thick cards, photos, or multiple inserts.

Decision rules for choosing a card format

• If your message is under 50 words: Choose a note card in A2 size. It is compact, uses a standard stamp, and fits a short thank-you or invitation. Best for quick notes and enclosure cards.
• If your message is over 50 words or includes a photo: Choose a folded greeting card in A7 size. The extra space and fold protect longer writing and a 5 x 7 photo. Best for birthdays, holidays, and updates.
• If you add thick embellishments or multiple inserts: Weigh the finished envelope or use a rigid mailer. Standard postage may not cover a stiff or heavy envelope. Check postage before mailing a batch.

Cards and stationery that pair well with mailing

• Deeri Pillow: Deeri Pillow comes with cover and pillow. A soft pillow is not a mailing supply, but it shows how a cover-and-insert set works: the cover protects the insert. Apply the same logic to cards by choosing an envelope that fully covers and protects the card.
• Mini Cappi the Capybara: Mini Cappi the Capybara is a small plush with a sleek tan coat and dark brown accents. Small plush characters like this are common enclosure gifts. If you plan to tuck a small plush into a card envelope, choose a larger greeting card size or a padded mailer, because a standard A2 envelope will not fit both comfortably.

Is this card format right for you?

Best for

• People who mail birthday, holiday, or thank-you cards regularly
• Crafters who want a simple envelope size guide
• Anyone sending a small photo or short note by mail

Not for

• Sending thick gifts or bulky items that need a box
• International mail where size and weight limits differ
• Anyone who wants a single card to fit every occasion without checking envelope sizes

Pick the format first, then the size: note card for short messages, greeting card for longer ones. Match the envelope to the card, keep cardstock mid-weight for mailing, and test one envelope before you send the rest. That routine keeps your cards flat, properly stamped, and ready to arrive as intended.