Paper sizes are commonly measured in terms of length and width. The two most common paper sizes are the ATLAS size, which measures 11 x 17 inches, and the Potts size, which measures 8.5 x 11 inches. ATLAS is the larger of the two sizes and is often used for posters, maps, and other large-format documents. Potts is the smaller size and is commonly used for printing documents such as letters, reports, and brochures.