Square inch

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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:

• square in
• sq inches, sq inch, sq in
• inches/-2, inch/-2, in/-2
• inches^2, inch^2, in^2
• inches², inch², in² (also denoted by "²)
• historic engineering drawings ^□″ (number with a square & a double apostrophe, both as an exponent)

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.