A square inch (plural: square inches) is a unit of area, equal to the area of a square with sides of one inch. The square inch is a common unit of measurement in the United States and the United Kingdom. Pounds per square inch (psi), a unit of pressure, are derived from this unit of area.

Representations

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 usage □″ (number with a square & a double apostrophe, both as an exponent)

Equivalence with other units of area

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

• square feet (1 square foot is equal to 144 square inches)

• square yards (1 square yard is equal to 1,296 square inches)

• square centimetres (1 square centimetre is equal to square inches)

• square metres (1 square metre is equal to square inches)

• circular inches (1 circular inch is equal to square inches)

References

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