11. Lesson Eleven: Real Estate Math
The American National Standards Institute (ANSI) guidelines on how to calculate a home’s square footage are considered the standard, but there are no official laws that govern this process. In addition, some Multiple Listing Services (MLS) report all finished and unfinished square footage as one number, adding to the confusion. As a result, buyers and their agents often have to investigate.
Residential Square Footage Guidelines
1 foot = 12 inches
1yard = 3 feet
1 sq. yard = 9 sq. feet (3 ft. x 3 ft.)
1 cubic yard = 27 cubic feet (3 ft. x 3 ft. x 3 ft.)
When reporting square footage, real estate agents should carefully follow these Guidelines or any other standards that are comparable to them, including those approved by the American National Standards Institute, Inc. (ANSI).
Living Area Criteria
Living area (sometimes referred to as “heated living area” or “heated square footage”) is space that is intended for human occupancy and is:
- Heated by a conventional heating system or systems (forced air, radiant, solar, etc.) that are permanently installed in the dwelling (not a portable heater) which generates heat sufficient to make the space suitable for year-round occupancy;
- Finished, with walls, floors and ceilings of materials generally accepted for interior construction (e.g., painted drywall/sheet rock or paneled walls, carpeted or hardwood flooring, etc.) and with a ceiling height of at least seven feet, except under beams, ducts, etc. where the height must be at least six feet four inches [Note: In rooms with sloped ceilings (e.g., finished attics, bonus rooms, etc.) you may also include as living area the portion of the room with a ceiling height of at least five feet if at least one-half of the finished area of the room has a ceiling height of at least seven feet.]; and
- Directly accessible from other living area (through a door or by a heated hallway or stairway). Real estate appraisers and lenders generally adhere to more detailed criteria in arriving at the living area or “gross living area” of residential dwellings. This normally includes distinguishing “above-grade”from “below-grade”area, which is also required by many multiple listing services.
Real estate agents are permitted to report square footage of the dwelling as the total “living area” without a separate distinction between “above-grade” and “below-grade” areas.
“Above-Grade” is defined as space on any level of a dwelling which has living area and no earth adjacent to any exterior wall on that level.
“Below-Grade” is space on any level which has living area, is accessible by interior stairs, and has earth adjacent to any exterior wall on that level.
Living area (sometimes referred to as “heated living area” or “heated square footage”) is space that is intended for human occupancy.
Basements & Attics
- Regardless of whether or not they are finished, basements do not typically count towards a home’s gross living area.
- Since they are below the grade of the rest of the home, basements can’t be included in the total square footage.
- Professionals may note the size of a finished basement.
- Attics may be counted in a home’s total square footage if they are finished.
The amount of living area dwellings is based upon exterior measurements except for condominiums, which use interior measurements.
A tape measure that indicates linear footage in “tenths of a foot” will greatly simplify your calculations. When measuring a structure, you should measure to the nearest tenth of a foot.
Real estate agents are expected to be able to accurately calculate the square footage of most dwellings.
An agent is expected to use reasonable skill, care and diligence when calculating square footage.
What is a good management technique to protect yourself from false accusations?
Maintain a written record.
Formula for rectangle Area = Length x width
Formula for square Area = side x side
Formula for triangle Area = base x height x 0.5
Knowing how to measure square footage can be very useful for real estate rental and sale purposes, and it can also help you ace your next geometry test. To measure the square footage of a space, separate the space into manageable parts, find the square footage of all those different parts (usually by multiplying length times width), and add the square footage of all separate parts together to find the square footage of the overall space.
Find the Square Footage of a Space
Break down the area into manageable parts. I
if you’re having trouble finding the square footage, then it’s probably because you’re not working with a neat area with just one length and one width.
The space might have squares jutting off in different places and could be shaped erratically.
All you have to do is split up the space into even squares or rectangles.
To find the square footage, or the area, of the entire space, you’ll need to find the square footage of the individual spaces and then add them all together.
Draw faint lines separating the different sections.
Label them A, B, and C for your convenience.
Measure the length and width of the first space. Using a ruler or measuring tape, find the length and width of the first space you’ve created, Space A.
Measure the length and width of the second space.
Multiply the length of the second space times the width of the second space.
This will lead you to find the square footage of the second space. Here’s how you find the square footage of Space B:
Measure the length and width of the third space.
Add the square footages of the three spaces.
Once you find the sum of the square footages of the three spaces, you’ll know the square footage of the entire space.
Here’s how you do it:
Square footage of Space A + square footage of Space B + square footage of Space C = square footage of the entire space
Learn a Few Tricks for Finding Square Footage
Find the approximation of square footage.
If you’re looking for an approximation of square footage, you can also try measuring the outside of your home and then subtracting any areas that won’t be factored in to the square footage, such as the porch stairs or garage.
Ceiling and floor tiles are often one square foot in size. You can simply count these to get a close approximation of the total square footage.
Find the square footage of a space that’s shaped like a half-circle.
If there’s a part of your house that’s shaped like a half of a circle, you can find the square footage of the circle by finding the area of the space as if it were a full circle and then dividing it by half.
To do this, simply measure the long line that cuts the “circle” in half to get the diameter.
Next, divide that number by 2 to get the radius (r)
Finally, divide by 2 to get the area, or square footage, of the half circle.
Find the square footage of a space that’s almost regularly shaped.
If you’re measuring a space that is almost fully a square or a rectangle, with only a small square or rectangular part missing, then measure the square footage of the entire space as if the missing part was filled in. Then, find the square footage of the missing part and subtract it from the overall square footage to find the square footage of the space. This will save you time.