Square inches (sq in or in) is a unit of area used in the imperial system. It is defined as the area of a square with sides that are one inch long. Square inches are commonly used to measure the area of small objects, such as paper, fabric, or tiles.
There are several ways to calculate the area of an object in square inches. One way is to use the formula A = l x w, where A is the area, l is the length, and w is the width. For example, if you have a piece of paper that is 8 inches long and 5 inches wide, the area of the paper would be 8 x 5 = 40 square inches.