Greeting Card Size Guide: A1, A2, A6, A7 and More

Quick Answer

For most everyday cards, A2 (4.25" x 5.5") is the standard size that fits a brief note and mails with a single first-class stamp. Choose A7 (5" x 7") when you want more room to write or a photo insert. A6 (4.5" x 6.25") sits between them and works well for slightly longer messages. A1 is best for tiny enclosure cards or gift tags.

The Core Sizes You'll Actually See

Most greeting cards follow the A-series paper sizes, which are based on a simple ratio. The ones you'll encounter most often are A1, A2, A6, and A7. A1 measures 3.5" x 4.875" and is often used for enclosure cards or small thank-yous. A2 is 4.25" x 5.5", the classic note card size. A6 is 4.5" x 6.25", a bit larger and good for a paragraph or two. A7 is 5" x 7", the standard for photo cards and invitations. Knowing these dimensions helps you pick an envelope and estimate postage.

How to Match Cards to Envelopes

Each card size has a corresponding envelope, usually named with the same A-number. For example, an A2 card fits an A2 envelope (4.375" x 5.75"). A7 cards use A7 envelopes (5.25" x 7.25"). The slight extra space makes it easy to slide the card in and out. If you're buying cards that come with envelopes, like many from The Card Bureau, check the product details to confirm the envelope is included. For cards without envelopes, you can buy them separately—just match the A-size.

A6 vs A7: Which Should You Choose?

The main difference between A6 and A7 is writing space and visual impact. A6 is 4.5" x 6.25", while A7 is 5" x 7". If you plan to write a longer message or include a small photo, A7 gives you more room. A6 is a good middle ground if you want something a bit more substantial than A2 but don't need a full 5x7. A7 also tends to cost more to mail if it exceeds the standard envelope size. For a typical birthday or holiday card, A6 is often sufficient. For weddings or special announcements, A7 is the go-to.

Why Card Size Matters for Mailing

Postage rates depend on the size and weight of your envelope. In the U.S., a standard first-class stamp covers envelopes up to 6.125" x 11.5" and 1/4" thick. A2 and A6 cards typically fall within this range. A7 cards may require additional postage if they are rigid or over 1/4" thick. Always check with your local postal service for current rates. If you're hand-delivering, size is less of a concern, but a larger card can be harder to carry in a small bag.

When to Use Specialty Sizes

Beyond the A-series, you'll find square cards (often 5.5" x 5.5") and long slim cards (like 4" x 9"). Square cards usually require extra postage because they are non-machinable. Slim cards are great for a short message and fit in a #10 envelope. If you're making your own cards, you can cut paper to any size, but standard sizes make envelope shopping easier. For store-bought cards, the size is usually listed in the product description. For instance, The Card Bureau's cards are typically A2 size (4 1/4" x 5 1/2"), which is a versatile everyday option.

Decision Rules for Choosing a Card Size

• If you want a simple note that mails with one stamp: Choose A2 (4.25" x 5.5"). It's the most common size for everyday cards and fits standard envelopes. A2 is your default for birthdays, thank-yous, and quick hellos.
• If you need more writing space or plan to include a photo: Go with A7 (5" x 7"). It offers a larger canvas and is standard for photo cards and invitations. Check postage if the card is thick or rigid.
• If you want a middle ground between A2 and A7: Consider A6 (4.5" x 6.25"). It's larger than A2 but not as big as A7, giving you extra room without extra postage in most cases. A6 works well for holiday cards and longer messages.
• If you're making your own cards or buying envelopes separately: Match the card size to the envelope size. A2 cards need A2 envelopes, A7 cards need A7 envelopes, and so on. Buying cards that include envelopes, like those from The Card Bureau, eliminates the guesswork.

Card Sizes in The Card Bureau Catalog

• Family Plan Card: Family Plan Card is A2 size (4 1/4" x 5 1/2") and includes a kraft envelope and sleeve. A2 is the standard note card size, so it fits common A2 envelopes and mails with a standard stamp.
• Wine Filled Mother's Day Card: Wine Filled Mother's Day Card is 4.25" x 5.5" and includes a recycled kraft envelope. This matches A2 dimensions, making it easy to find compatible envelopes and send without extra postage.
• Made of Money Mother's Day Card: Made of Money Mother's Day Card is 4.25" × 5.5" and comes with a recycled Kraft envelope. The standard size means it can be framed or displayed easily and fits standard card displays.
• Didn't Request Birthday: Didn't Request Birthday card is A2 size (4 1/4" x 5 1/2") with a kraft envelope and sleeve. A2 is a popular size for humorous cards, and the included envelope saves you a separate purchase.

Is a Standard A2 Card Right for You?

Best for

• Everyday occasions like birthdays, thank-yous, and get-well wishes
• Sending a short, heartfelt message without extra postage
• People who want a card that fits standard frames or card displays

Not for

• Writing a long letter or including multiple photos
• Formal invitations or announcements that require a larger format
• Those who prefer a square or oversized card for visual impact