You can't. The inch is a measure of length; the square foot is a measure of area.
To convert SQUARE inches to square feet, divide the number of square inches by 144. (Since there are 12 inches in a foot, there are 12 x 12 = 144 square inches in a square foot.)
You can't convert that. You can convert feet to inches, or square feet to square inches.
18.5 square feet = 2664 square inches
That depends what you want to convert it to. To convert to square feet, divide by 144.That depends what you want to convert it to. To convert to square feet, divide by 144.That depends what you want to convert it to. To convert to square feet, divide by 144.That depends what you want to convert it to. To convert to square feet, divide by 144.
Multiply by 144, so: 2 square feet = 288 square inches
I assume you mean a rectangle. You can:* Convert everything to feet, then multiply; or: * First multiply, then divide the result (which is in square inches) by 144, to convert to square feet.