IN3

IN3, or similar, may refer to:
 * cubic inch (in3), a unit of volume
 * Indiana State Road 3, a road in the eastern part of the U.S. state of Indiana.
 * Indiana's 3rd congressional district, a congressional district in the U.S. state of Indiana
 * Internet Interdisciplinary Institute, the research body of the Open University of Catalonia
 * Iodine azide, chemical formula IN3