When purchasing siding you’ll hear the term “square” used a lot. In short, it’s how siding is measured. One square of siding is 100 square feet of siding material. Though the term siding square is more common to use when referring to how to measure for vinyl siding, it’s still used among other materials as well. Using a house siding calculator like the Lowe’s siding calculator will provide you with how many squares your project will need.