Some common paper sizes used in North America include letter, legal, junior legal, ledger and tabloid. Outside of the United States, Canada and Mexico, however, the most common paper sizes are defined by the ISO 216 standard.
Letter size paper is 8.5 inches wide by 11 inches long. Legal size paper has the same width as letter size paper but has an extended length of 14 inches. Junior legal size paper is 5 inches wide by 8 inches long, and ledger size paper is one of the largest commonly used North American paper sizes at 11 inches wide by 17 inches long. Tabloid size paper is the inverse of ledger size paper at 17 inches wide by 11 inches long.
Although North American paper sizes do not follow the ISO standard, letter and ledger size paper follow the ANSI standard. Letter size paper corresponds with ANSI A while ledger size paper corresponds with ANSI B. There are also ANSI C, D and E paper sizes, but these are much less commonly used.