No. Only the space that is above ground is included in the square footage of a house. Even if you have an extra 1000 square feet of living space because you have a finished basement, this is not included in the measurement of the size of your house. In addition, attics are generally not counted either in the square footage of a home (an attic is considered “unlivable” space). So don’t be deceived when looking at listings! Just because you see a house listed at 1500 square feet – if it has a finished basement, you can increase your livable space.