ProPackInsights lists the standard greeting card size in the US as 5 x 7 inches (12.7 x 17.8 cm) folded, known as A7. The common smaller size is A2 at 4.25 x 5.5 inches (10.8 x 14 cm). Most birthday, Christmas, and holiday cards use one of these two, and each pairs with a matching envelope.
Choosing the wrong card size means reprinting, surprise postage, or a card that rattles in its box. We built this guide for buyers who need exact figures before they order. Every size below lists folded dimensions, the envelope that fits, and the decision it affects. For packaging that fits your finished card line, browse our packaging guides.
Standard Greeting Card Sizes Are 5 x 7 and 4.25 x 5.5 Inches
The standard greeting card size is 5 x 7 inches (12.7 x 17.8 cm) folded, and the common smaller alternative is 4.25 x 5.5 inches (10.8 x 14 cm). Retail brands default to 5 x 7 for display racks and photo space. Small-batch makers favor the smaller format to control paper and postage cost. The table lists standard greeting card dimensions in inches and cm with the matching envelope.
| Name | Folded (in) | Folded (cm) | Envelope (in) |
| 4-bar | 3.5 x 4.875 | 8.9 x 12.4 | 3.625 x 5.125 |
| A2 | 4.25 x 5.5 | 10.8 x 14.0 | 4.375 x 5.75 |
| A6 | 4.5 x 6.25 | 11.4 x 15.9 | 4.75 x 6.5 |
| A7 | 5 x 7 | 12.7 x 17.8 | 5.25 x 7.25 |
| A9 | 5.5 x 8.5 | 14.0 x 21.6 | 5.75 x 8.75 |
| Square | 5 x 5 | 12.7 x 12.7 | 5.25 x 5.25 |
| Square | 6 x 6 | 15.2 x 15.2 | 6.25 x 6.25 |
Why 5 x 7 Became the Retail Default
The average size of a card on a store shelf is 5 x 7 because it balances three needs:
- It leaves room for artwork, a photo, and a written message.
- A7 envelopes are stocked almost everywhere.
- It reads as a card rather than a flyer.
We recommend 5 x 7 as the starting point for any new custom line.
Folded Size Versus Flat Print Size
Every size above is quoted folded, but the print file is built flat. A 5 x 7 card prints on a 10 x 7 sheet, a 4.25 x 5.5 card on 8.5 x 5.5, and an A6 card on 9 x 6.25. Confirming which measurement a supplier quotes prevents the most common ordering mistake. Card sizes also list width first and height second, as our guide to what width and length mean in packaging measurements explains.
A2 Card Dimensions Suit Small Runs and Note Cards
An A2 card measures 4.25 x 5.5 inches folded (10.8 x 14 cm). It suits thank-you notes, short greetings, and small runs where paper cost matters.
A2 Measurements in Inches and cm
The A2 card size in inches is 4.25 x 5.5 when folded and 8.5 x 5.5 flat for a side fold. In centimeters, the folded card is 10.8 x 14.0.
Paper Yield on a Letter Sheet
Two A2 flats cut from one 8.5 x 11 sheet with no waste. An A7 flat is 10 x 7, so it does not fit a letter sheet and needs larger stock. That difference is why A2 costs less per card on short runs.
A2 Envelope Match
The A2 envelope is 4.375 x 5.75 inches. Its length to height ratio is about 1.31, which leaves little margin against the postal aspect ratio rule covered below.
A5, A6, and A7 Card Sizes Differ Between US and ISO Systems
A5, A6, and A7 name different sizes in the US and ISO systems, so the same label can describe two cards of very different dimensions. Confirm the system before approving an order.
US A-Series Card Sizes
In US stationery, the A-series names come from envelope sizing. An A6 card is about 4.5 x 6.25 inches, and some suppliers list 4.625. An A7 card is 5 x 7, and some suppliers list 5.125. An A9 card is 5.5 x 8.5.
ISO 216 Sizes in Millimeters
ISO 216 sizes are based on the metric paper series. An A5 card is 148 x 210 mm (5.83 x 8.27 in). An A6 card is 105 x 148 mm (4.13 x 5.83 in). An A7 card is 74 x 105 mm (2.9 x 4.1 in), roughly pocket size and far smaller than a US A7.
How to Confirm the Size With Your Printer
State dimensions in both inches and millimeters on every purchase order. Ask whether the figure is folded or flat, and request a printed proof before the full run.
Birthday Card Size Follows the Retail 5 x 7 Standard
The standard birthday card size is 5 x 7 inches folded (12.7 x 17.8 cm). The typical birthday card size stays there because it matches what buyers see on shelves and fits the widely stocked A7 envelope.
Square formats at 5 x 5 or 6 x 6 inches give a modern look but need square envelopes, which affect postage. An A2 card works for small gift enclosures, such as a tag tied to a jar, and our guide to mason jar sizes helps you size the gift set around it. Oversized novelty cards reach 5.5 x 8.5 inches, at the cost of a larger envelope and more paper.
Christmas and Holiday Card Size Depends on Photo and Mailing Needs
The standard Christmas card size is 5 x 7 inches, either as a folded A7 card or a flat photo card, with A6 and square formats as common alternatives. Holiday runs of several hundred cards multiply any per-piece postage difference, so the format choice matters more here than for single cards. For storing and shipping runs that size, our bankers box dimensions guide lists standard outer carton sizes.
5 x 7 Flat Photo Cards and Folded A7
A flat 5 x 7 card puts the photo on one side and the message on the other. A folded A7 gives the same face size plus interior space for a longer note.
A6, 4-Bar, and Square Holiday Formats
An A6 card at 4.5 x 6.25 inches runs slightly more compact. A 4-bar card at 3.5 x 4.875 inches suits small enclosures. A 5 x 5 square looks modern but needs a square envelope.
Gift Card Size Follows the CR80 Standard
The standard gift card size is 3.375 x 2.125 inches (85.6 x 54 mm), the CR80 format used by credit cards and defined in ISO/IEC 7810 as ID-1. Card carriers and holders vary by supplier, so measure the holder’s window against 3.375 x 2.125 before ordering.
Envelope and Postage Fit Decide the Final Card Size
The envelope decides the final card size because the card must clear the envelope and meet USPS letter rules. Confirm current rules at the USPS Quick Service Guide for commercial letters.
Envelope clearance rules:
- Choose an envelope 0.125 to 0.25 inch larger than the folded card.
- Match A-series cards to the same A-series envelope.
- Test one assembled sample before ordering envelopes in bulk.
Postage checks before printing:
- USPS letter dimensions run from 5 by 3.5 inches up to 11.5 by 6.125 inches, with thickness from 0.007 inch to 0.25 inch.
- A length to height ratio below 1.3 or above 2.5 makes a letter nonmachinable, and a square envelope has a ratio of 1. Nonmachinable pieces may carry a surcharge.
- The A7 envelope (5.25 x 7.25) has a ratio near 1.38, and the A6 envelope (4.75 x 6.5) is near 1.37.
| Occasion | Folded size (in) | Envelope |
| Birthday | 5 x 7 | A7 |
| Thank-you | 4.25 x 5.5 | A2 |
| Christmas | 5 x 7 or 4.5 x 6.25 | A7 or A6 |
| Invitation | 5 x 7 | A7 |
Print Setup and Packaging Fit Protect Custom Card Orders
Custom card orders need 0.125 inch of bleed and a safe margin on the flat file, and packaging must be sized to the folded card plus its envelope. Both checks prevent reprints and transit damage.
Bleed, Safe Margin, and Resolution
Extend artwork 0.125 inch past the trim on every edge, so a flat 10 x 7 file becomes 10.25 x 7.25. Keep text at least 0.125 inch inside the trim. Supply files at 300 DPI in CMYK.
Paper Weight and Score Lines
Heavier cover stocks crack at the fold unless they are scored first. Ask the printer to score the fold and to run the grain parallel to it.
Sleeves, Boxes, and Mailers for Card Sets
Size packaging to the envelope, not the card. A set of A7 envelopes (5.25 x 7.25) needs an interior of about 5.5 x 7.5 inches before you add stack height. For a retail carton around a card set, our guide to cereal box dimensions shows how carton height, width, and depth are measured. Test one packed set for fit and corner protection before approving a production run.
FAQs
What is the standard size of a greeting card?
The standard greeting card is 5 x 7 inches (12.7 x 17.8 cm) folded, known as A7. It fits an A7 envelope at 5.25 x 7.25 inches.
What size is an A2 card?
An A2 card is 4.25 x 5.5 inches (10.8 x 14 cm) folded. It prints flat at 8.5 x 5.5 inches and uses an A2 envelope.
How big is a birthday card?
Most birthday cards are 5 x 7 inches folded. Square 5 x 5 and 6 x 6 cards are common alternatives.
Is a 5 x 7 card measured folded or flat?
Card sizes are quoted folded, so a 5 x 7 card prints on a 10 x 7 flat sheet. Always confirm which measurement a supplier lists.
What is the standard Christmas card size?
The standard Christmas card size is 5 x 7 inches, either folded A7 or a flat photo card. A6 at 4.5 x 6.25 inches is a common smaller option.
What size is a standard gift card?
A standard gift card is 3.375 x 2.125 inches (85.6 x 54 mm), the CR80 format.
