What Are the Dimensions of a Birthday Card? Standard Sizes Guide
The most common US folded birthday card size is 5 × 7 inches (12.7 × 17.8 cm). Smaller formats, such as 4.25 × 5.5 inches, and square cards are also widely used. The right size depends on the design, the amount of space needed for a message, and the envelope you plan to use.
Whether you're buying a birthday card, making one at home, or preparing artwork for printing, this guide covers standard birthday card dimensions in inches, centimeters, and millimeters, along with folded and flat sizes, envelope measurements, and birthday invitation formats.
Standard Birthday Card Sizes at a Glance
These are common US folded card formats. Dimensions refer to the closed card unless otherwise noted.
Card formatFolded size (inches)Approx. folded size (cm)Typical useA24.25 × 5.5 in10.8 × 14 cmSmall cards and short greetingsA6 (US card format)4.5 × 6.25 in11.4 × 15.9 cmPersonal greetings and photo cardsA7 (US card format)5 × 7 in12.7 × 17.8 cmGeneral-purpose birthday cardsA95.5 × 8.5 in14 × 21.6 cmLarger cards with more writing spaceSquare5 × 5 in12.7 × 12.7 cmCompact, modern designsLarge square6 × 6 in15.2 × 15.2 cmPhoto cards and distinctive designsThese are commonly used formats, not universal requirements. Manufacturers may offer different dimensions, so check the finished card size and compatible envelope before ordering or printing.
What Is the Standard Birthday Card Size?
A common US birthday card size is 5 × 7 inches (12.7 × 17.8 cm) when folded. It provides space for a front-cover design and an inside message while fitting a widely available envelope format.
There is no single required size for every birthday card. A smaller card may work well for a short greeting, while a larger or square format can suit photographs, detailed artwork, or messages from several people.
Use these guidelines when choosing a size:
For a short greeting: A smaller folded card can be sufficient.
For a handwritten message: A 5 × 7-inch card offers comfortable writing space.
For photographs: Consider a 5 × 7-inch or square format.
For a group card: Choose a larger card with enough room for multiple signatures.
For a distinctive design: A square or custom format can create a different look.
Birthday Card Dimensions in Inches
If you're using US measurements, the following table shows common folded sizes and the approximate dimensions of the flat sheet before folding.
FormatFolded dimensionsFlat dimensions before foldingA24.25 × 5.5 in8.5 × 5.5 inA6 (US card format)4.5 × 6.25 in9 × 6.25 inA7 (US card format)5 × 7 in10 × 7 inA95.5 × 8.5 in11 × 8.5 inSquare5 × 5 in10 × 5 inLarge square6 × 6 in12 × 6 inThe flat dimensions assume a single fold that doubles one dimension of the finished card. The orientation of the fold determines how the card opens.
Standard Birthday Card Size in Centimeters
For metric measurements, these are approximate conversions of common US card formats.
FormatFolded dimensionsFlat dimensions before foldingA210.8 × 14 cm21.6 × 14 cmA6 (US card format)11.4 × 15.9 cm22.9 × 15.9 cmA7 (US card format)12.7 × 17.8 cm25.4 × 17.8 cmA914 × 21.6 cm27.9 × 21.6 cmSquare12.7 × 12.7 cm25.4 × 12.7 cmLarge square15.2 × 15.2 cm30.5 × 15.2 cmThese conversions are rounded. For a print order, use the exact dimensions specified by your printer.
Birthday Card Dimensions in Millimeters
Millimeters are useful when preparing print files or checking measurements with a printing service.
FormatFolded dimensionsA2108 × 140 mmA6 (US card format)114 × 159 mmA7 (US card format)127 × 178 mmA9140 × 216 mmSquare127 × 127 mmLarge square152 × 152 mmProduction dimensions may vary slightly by supplier. Before printing, confirm the finished size, bleed, and trimming requirements.
US Card Sizes vs. International A-Series Paper Sizes
Card-size labels can be confusing because some US greeting-card formats use names such as A2, A6, and A7, while international paper sizes follow the ISO A-series system. The two naming systems are not interchangeable.
For example:
A US A7 greeting card commonly measures 5 × 7 inches (127 × 178 mm).
ISO A7 paper measures 74 × 105 mm.
ISO A6 paper measures 105 × 148 mm (10.5 × 14.8 cm).
ISO A5 paper measures 148 × 210 mm (14.8 × 21 cm).
Square cards are also sold in metric sizes, such as 15 × 15 cm, depending on the manufacturer.
If you're ordering cards internationally, confirm the actual width and height rather than relying on a format name alone.
Flat vs. Folded Birthday Card Dimensions
Birthday card dimensions usually describe the finished card when it is closed. The flat size is the sheet's measurement before it is folded.
For example, a folded card measuring 5 × 7 inches typically starts as a flat sheet measuring 10 × 7 inches.
Folded size: The dimensions of the closed card.
Flat size: The dimensions of the unfolded sheet before folding.
Print-file size: The dimensions required for the artwork, potentially including extra bleed around the edges.
Always check which measurement a supplier needs. Confusing the flat size with the folded size can result in artwork that is too large or too small.
Portrait vs. Landscape Birthday Cards
Portrait and landscape describe a card's orientation, not its physical size. A 5 × 7-inch card can be designed in either orientation.
Portrait orientation
A portrait card is taller than it is wide when viewed from the front. It can suit vertical illustrations, floral designs, large lettering, and traditional birthday greetings.
Landscape orientation
A landscape card is wider than it is tall when viewed from the front. It can work well for group photos, scenic artwork, panoramic illustrations, and horizontal layouts.
Choose the orientation based on the design and the way you want the card to open and display.
Square Birthday Card Sizes
Square birthday cards offer an alternative to traditional rectangular formats. Common examples include 5 × 5 inches (12.7 × 12.7 cm) and 6 × 6 inches (15.2 × 15.2 cm).
A square layout can suit photo-based cards, minimalist artwork, geometric designs, and cards featuring one central illustration.
Before mailing a square card, check the postal rules for your destination. Depending on the country, its dimensions, thickness, or shape may affect postage.
Oversized Birthday Card Dimensions
Oversized cards provide more room for large designs or messages from multiple people. They can be useful for office celebrations, milestone birthdays, classroom gifts, and group greetings.
Possible formats include:
8 × 10 inches: A larger presentation-style card.
8.5 × 11 inches: A convenient starting format when working with US letter-size paper.
Custom large formats: Useful when many people need space to write or sign.
These are examples rather than universal standards. Check how the card will be folded, displayed, packaged, and delivered before choosing a custom size.
What Size Envelope Fits a Birthday Card?
The envelope should be slightly larger than the closed card so the card can slide in without being forced. Common US envelope pairings include the following.
Folded card sizeCommon envelope size4.25 × 5.5 in (A2 card)4.375 × 5.75 in (A2 envelope)4.5 × 6.25 in (US A6 card)Check the supplier's matching envelope specifications5 × 7 in (US A7 card)5.25 × 7.25 in (A7 envelope)5.5 × 8.5 in (A9 card)5.75 × 8.75 in (A9 envelope)Envelope names and dimensions can vary by supplier and market. Confirm the actual measurements before purchasing, especially if the card has thick embellishments, layered paper, or pop-up features.
What Is the Standard Birthday Invitation Size?
Birthday invitations are available in several formats depending on the design and the amount of information included. A 5 × 7-inch invitation is a common option, while 4 × 6-inch formats and square invitations are also used.
When choosing an invitation size, consider:
Information: Leave room for the date, time, location, RSVP details, and any additional instructions.
Design: Photos or detailed illustrations may need more space.
Envelope: Choose a compatible envelope before finalizing the artwork.
Delivery: Check the mailing requirements if the invitations will be posted.
Explore our birthday invitation cards if you're looking for designs for an upcoming celebration.
How to Choose the Right Birthday Card Size
The best size depends on what you want the card to accomplish.
Your goalFormat to considerWhyA short, simple birthday wishSmall folded cardCompact and easy to include with a giftA standard greeting with room to write5 × 7 in foldedBalances writing space and practicalityA photo or detailed front design5 × 7 in or squareProvides room for artwork and imagesA group messageLarge folded cardAllows several people to write insideA distinctive visual layoutSquare or custom formatCreates a different shape and presentationA printed invitation5 × 7 in or 4 × 6 inProvides room for event detailsIf you're choosing a card for someone else, dimensions are only one part of the decision. The design, message, and personalization also help make the card appropriate for the occasion.
Tips for Designing and Printing a Birthday Card
If you're making your own card or preparing a design for a print shop, a few checks can help prevent common problems.
Confirm the finished size. State whether the dimensions are folded or flat.
Check the envelope first. Match the card to the actual envelope before finalizing the layout.
Use high-resolution images. Follow the printer's recommendations; 300 DPI is a common target for print artwork.
Leave safe margins. Keep text and important design elements away from trimming edges and fold lines.
Ask about bleed. If the background extends to the edge, the printer may require artwork beyond the final trim size.
Check the fold direction. Make sure the artwork is oriented correctly on the flat sheet.
Request a proof. For a large print run, review a proof before approving the full batch.
For a handmade card, use sturdy paper and test the fold before adding bulky decorations. For commercial printing, follow the print provider's template rather than assuming all suppliers use identical requirements.
Frequently Asked Questions
What is the standard size of a birthday card?
A common US birthday card size is 5 × 7 inches (12.7 × 17.8 cm) when folded. Smaller formats, including 4.25 × 5.5 inches, and square cards are also widely used.
What is the standard birthday card size in centimeters?
A folded 5 × 7-inch birthday card measures approximately 12.7 × 17.8 cm. Other common formats include 10.8 × 14 cm for a US A2 card and 15.2 × 15.2 cm for a 6 × 6-inch square card.
How big is a normal birthday card?
Many folded birthday cards are around 5 × 7 inches, but there is no single required size. Small cards, square designs, and larger formats are also available.
What is the standard greeting card size in inches?
A common US greeting-card format is 5 × 7 inches folded. Other frequently used formats include 4.25 × 5.5 inches and 5.5 × 8.5 inches. For a broader comparison across occasions, see our greeting card size guide.
Are US A7 cards the same as ISO A7 paper?
No. A US A7 greeting card commonly measures 5 × 7 inches (127 × 178 mm). ISO A7 paper measures 74 × 105 mm. The names belong to different sizing conventions, so check the actual dimensions when ordering.
What size envelope fits a 5 × 7-inch birthday card?
A common US pairing is a 5.25 × 7.25-inch A7 envelope for a folded 5 × 7-inch card. Check the supplier's specifications, especially if the card has thick decorations or multiple layers.
What size should a homemade birthday card be?
A folded 5 × 7-inch card is a practical choice for many homemade designs because it provides space for artwork and a message. A smaller or square format can work just as well if it suits your design and fits the envelope you have chosen.
What size is a birthday invitation?
A 5 × 7-inch invitation is a common option, while 4 × 6-inch and square formats are also used. Choose a size that accommodates the event details and matches the envelope and delivery method.
How much does a birthday card weigh?
The weight depends on the paper stock, card dimensions, number of layers, decorations, and envelope. A flat paper card will generally weigh less than a thick pop-up or embellished card. If you're mailing it, weigh the finished card inside its envelope and check the postal service's current requirements.
Choose the Right Birthday Card Format
Birthday card dimensions affect how the design looks, how much space is available for a message, and which envelope you can use. A folded 5 × 7-inch card is a versatile option, but smaller, square, and oversized formats can work better for particular designs.
Before printing or ordering a card, confirm the finished dimensions, envelope size, and production requirements. Once the format is right, you can focus on choosing a design and message that makes the birthday greeting feel personal.
If you're looking for a professionally designed option, browse our personalized birthday cards and choose a style that suits the recipient and occasion.