<P> Letter or ANSI Letter is a paper size commonly used as home or office stationery in the United States, Canada, Chile, Mexico, the Dominican Republic and the Philippines . It measures 8.5 by 11 inches (215.9 by 279.4 mm). US Letter - size paper is a standard defined by the American National Standards Institute (ANSI, paper size A), in contrast to A4 paper used by most other countries, and adopted at varying dates, which is defined by the International Organization for Standardization, specifically in ISO 216 . </P> <P> The Reagan administration made Letter - size paper the norm for U.S. federal forms in the early 1980s; previously, the smaller "official" Government Letter size, 8 by 10.5 inches (203.2 by 266.7 mm), was used in government, while 8.5 - by - 11 - inch (215.9 by 279.4 mm) paper was standard in most other offices . </P>

8 and a half by 11 paper size