Knowing the square footage of your home or one you may buy is crucial. Square footage is the baseline metric by which value is calculated, so be sure you have an accurate number.
Why square footage is important
The square footage of a house is used to compute its value. An accurate number is essential for the following reasons.
- The county will set the amount of property taxes you owe on your house based on the average value per square foot.
- A seller and agent must provide accurate square footage to the Multiple Listing Service (MLS) and set an asking price based on the square footage. The MLS can fine sellers who provide inaccurate square footage. The listing agent may also be held responsible for the error, as well as the broker-in-charge.
- A buyer must know precisely how many square feet she is buying to determine whether the asking price is fair. Buyers shouldn’t just assume the square footage information in a listing is accurate.
- A mortgage company needs an accurate appraisal value to make its lending decision.
- Knowing a home’s square footage is also critical when buying flooring.
So, all parties involved in the ownership, taxing, buying, or selling of a home have a stake in accurately calculating its square footage.
It is not enough to multiply a house’s exterior length and width. Floor plans are sometimes asymmetrical, and the upper floors often are not the same size as the lower floors.
Here’s how to calculate the square footage of a home.
You don’t have to be a mathematician.
Calculating square footage requires simple geometry. Many rooms are squares or rectangles. Even a room with a triangular flair to one side that ties into an alcove or short hall can be easily calculated.
Start by sketching the floor plan on graph paper. Do a separate sketch for each floor.
Using a measuring tape, determine the length and width of each room. Multiply those two numbers together, and you have the square footage of that room. Write that number into each room on your diagram.
If part of the floorplan is a triangle, multiply the length of the base (i.e., the longest side) by the height of the triangle. Then, multiply that number by .5 to determine the square footage.
Add up the square footage of every room to get the total square footage. Multiply that number by the average cost per square foot of comparable homes in the area to get the estimated value.
Rooms that do not count
What rooms count toward square footage? Rules vary by state, but generally, basements do not count toward square footage because they are below ground level. In some states, the answer may depend on whether the basement has a means of egress directly to the outside.
Garages generally do not count toward square footage, even if finished as living space. Attic space finished out as living space may count.
Armed with accurate square footage and comparable cost per square foot, you can determine whether your property tax bill is accurate, set a reasonable sales price when selling, or know whether a seller’s asking price is fair.
Related – What is the MLS?