Index Card Sizes

Index cards come in a variety of sizes, with some of the most common being 3x5, 4x6, and 5x7 inches. The 3x5 size is the most widely used and available, especially in North America. It provides a good amount of writing space while still being highly portable. 4x6 cards are also very popular in the United States and offer slightly more room to write. In Europe, the A7 (similar to 3x5 inches) and A6 (approx. 4x6 inches) sizes are commonly used. 5x7 cards provide even more writing real estate but are less portable and commonly used in North America. Some other sizes like 2x3 or 3x4 inches serve specialized purposes where minimal space is available. While there are regional differences, the 3x5 and 4x6 inch cards tend to be the most versatile and popular worldwide due to their blend of writing space and portability.