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square inch
Unit systemImperial, United States customary units
Unit ofarea
Symbolin2, sq in
1 in2 in ...... is equal to ...
  • 1/144 sq ft
  • 1/1296 sq yd
   SI units   
  • 6.4516 cm2
  • 6.4516×10−4 m2

A square inch (plural: square inches) is a unit of area, equal to the area of a square with sides of one inch. The following symbols are used to denote square inches:

The square inch is a common unit of measurement in the United States and the United Kingdom. A common unit of pressure, pound per square inch (psi) is derived from this unit of area.

Equivalence with other units of area

1 square inch (assuming an international inch) is equal to: (the overbars indicate repeating decimals)