"Letter size" refers to a standard paper size commonly used in the United States and Canada. It measures 8.5 inches by 11 inches (21.6 cm by 27.9 cm) and is often used for printing documents, letters, and forms. This size is part of the larger category of paper sizes defined by the American National Standards Institute (ANSI). In contrast to the international standard known as A4, which measures 8.27 inches by 11.69 inches (21 cm by 29.7 cm), letter size is more prevalent in North America. Many printers and office supplies are designed specifically for this size, making it a convenient choice for everyday use.