Foolscap is a paper size that historically had two prevalent sizes: British Foolscap and Imperial Foolscap. The British Foolscap measured approximately 8.0 by 13.0 inches (203 mm by 330 mm) and was widely used in the United Kingdom for official documents and administrative records. The Imperial Foolscap was slightly larger, measuring around 8.5 by 13.5 inches (216 mm by 343 mm) and was preferred in some regions of the British Empire for similar purposes. Today, in the United States, a half-foolscap sized paper for printing is standardized to 8+1⁄2 by 14 inches (216 mm × 356 mm), widely available and sold as "legal sized paper" for printing, writing, note-taking, etc. A full foolscap size paper of 14 by 17 inches (356 mm × 432 mm) is also widely available for arts and crafts, etc. alongside the 11 by 17 inches (279 mm × 432 mm) tabloid size.

In terms of comparison with other paper sizes, Foolscap is slightly larger than Letter paper size, measuring 13.0 inches by 8.0 inches (330 mm by 203 mm), while Letter is 11.0 inches by 8.5 inches (279 mm by 216 mm) .