When you buy a new home, thinking about how to measure its square footage probably isn’t top of mind. And while it may seem like an inconsequential metric, it’s one of the most important factors that determine a property’s value.
“If you mismeasure a property, it’s a domino effect — it’s going to throw the whole value off,” says Marlon Day, senior director of Quest Valuation & Advisors in Atlanta.
Square footage statistics
- The median price per square foot for a home in the U.S. is $123, according to data from Realtor.com. However, price per square foot can vary greatly depending on location.
- The average size of a home in the U.S. in 2020 was 2,261 square feet, per Statista. Its data shows that home sizes have decreased every year since 2017, when the median was 2,426 square feet.
- In 1950, the country’s average home size was 983 square feet, per the International Association of Certified Home Inspectors.
- The average bedroom size, according to CRD Design Build, is roughly 132 square feet. There are specific requirements regarding what can be considered a legal bedroom, including required square footage, ceiling height and modes of egress, which vary from state to state.
- The U.S. has the highest average number of rooms per person around the world, with 3.8 rooms per household member, according to data from international policy group the Organisation for Economic Cooperation and Development.
Why square footage is important
There are plenty of reasons you might want to know how to calculate the square feet of a house, whether you’re looking to sell a property, dispute a high tax assessment or renovate to add more space.
If you’re preparing to list your home for sale, determining the property’s exact size is a crucial factor when setting your asking price. “For a home appraisal, we’re going to compare it to comparables or ‘comps,’” says Day, who looks for homes of similar size in the immediate area. An inaccurate square footage measurement could potentially result in an inaccurate appraisal price.
Square footage (often abbreviated as SF or SQFT) also matters in real estate deals that involve a mortgage, for similar reasons. The lender will want that info to verify what the property is worth.
However, knowing your home’s square footage can come in handy in other ways as well. For instance, if you decide to finish a previously unused part of your house — say, a basem*nt or attic space — you may need to provide the square footage to obtain a building permit.
Likewise, if your county or municipality assesses higher taxes than what you think you should owe, confirming the square footage can be a point in your favor toward getting the property taxes reduced.
How to calculate the square footage of a house
When preparing to measure the square footage of a home, be it a house, condo, or townhouse, start with a few simple supplies:
- Paper and pencil
- Calculator
- Measuring tape and/or laser measuring tool
If the property is a perfect rectangle, simply measure the length and width and multiply those two numbers together. For example, if your one-story house is 60 feet wide by 40 feet long, then your property is 2,400 square feet (60 x 40 = 2,400).
However, most properties have more complex floor plans. When this is the case, it’s helpful to follow these simple steps to measure square footage.
- Draw a rough sketch of your entire space, labeling all of the rooms you need to measure. Include hallways and vestibules as their own “room.”
- Measure the length and width, in feet, of each room. Then, multiply the length by the width to calculate that room’s square footage. For example: If a bedroom is 12 feet by 20 feet, it is 240 square feet (12 x 20 = 240). For each room, write the total square footage in the corresponding space on your sketch.
- Once each room is measured, add up all the measurements to determine your home’s total square footage.
Note
If you live in a tract home, condo or townhome community, you may be able to get architectural drawings or master builder plans of your floor plan. These may already have your square footage calculated.
What to leave out
A good rule of thumb to ensure you’re taking proper measurements is to exclude space you can’t walk on or live in. These types of spaces do not count as “gross living area.”
“Someone might think, ‘If I get the measurement of my first floor and I have a two-story house, I just multiply that by two,’” Day says. However, if that first floor includes a two-story foyer, you can’t count the non-usable space.
Basem*nts and garages, even if they are finished, don’t generally count toward total square footage. Basem*nts are typically excluded because they are built below grade, meaning below ground level. If your state does allow basem*nts to be included in the total square footage of a home, though, you’ll likely need an ingress and egress, or a safe way to enter and exit the basem*nt to the outside.
Finished attic spaces — with some regulations, including ceiling heights — can count toward the total square footage of your home. If you are planning to sell your home, work with a real estate agent to craft a listing that accurately reflects your property.
When in doubt, ask the pros
If calculating the square feet of your particular property feels overwhelming, consider hiring a professional appraiser to do it. The average appraisal cost for a single-family home typically runs about $350. A condo appraisal fee is generally between $300 and $500, and multi-family home appraisals can run anywhere from $600 to $1,500.
While two different professional appraisers could evaluate the same home and come up with slightly different square footage figures, they do all aim for scientific accuracy. “We’re always shooting for somewhere between 1 to 3 percent variance,” Day says.
FAQs
Every appraiser has their own preferred method of calculating the square footage of a home. Some use a tape measure to carefully take the dimensions of each room, whereas others use a laser device that eliminates manual measuring. For difficult-to-measure spaces, experienced pros may just eyeball it. As a result, different appraisers will often come up with a slightly different square footage of the same home.
There are lots of reliable square footage calculators online, including examples from Calculator Soup, the Calculator Site or Calculator.net. Many can calculate price per square foot as well.
To calculate the square footage of a roof, start by measuring the length and width of every roof surface, including dormers. Then, multiply the length and width of each rectangular section of roof to find the area. If there are triangular sections of roof, calculate the area by multiplying the length of the triangle’s longest side by its height, and divide by two. The last step is to add up the area of all roof planes to get the total square footage of the roof.
You can calculate the square footage of a triangular room by measuring the base of the triangle, which is the length of the longest wall. Then, measure the height to the top of the triangle. Multiply the base and height together, and divide by two to get the square footage of the room.
Closets are often included in the square footage of a home, but not always. Any space inside a home that has walls, a floor, a ceiling and heat are usually counted toward the overall square footage. However, if there are closets that don’t meet the requirements, like in an unheated, unfinished basem*nt, they probably would not be counted.
FAQs
Measure the length and width, in feet, of each room. Then, multiply the length by the width to calculate that room's square footage. For example: If a bedroom is 12 feet by 20 feet, it is 240 square feet (12 x 20 = 240). For each room, write the total square footage in the corresponding space on your sketch.
What is not included in the square footage of a house? ›
It should be the footprint of the house, on the outside, that is measured. It is the livable space, heated and cooled, that is considered for square footage. Garages, decks, patios, porches, and the like are not considered part of that measurement.
How do you find the square footage of a triangle with unequal sides? ›
Simply square one of the side lengths: Area = side length (s) × side length (s) = s^2. Triangle: To find the area of a triangle, multiply its base (b) by its height (h) and divide by 2: Area = (base (b) × height (h)) / 2. C.
Is there an app that calculates square footage? ›
MeasureSquare RoomScanner App (Free)
A homeowner can use this app to create a floor plan and share it with their flooring contractors, remodelers and others to get a quote on their projects too.
What is the perfect square footage of a house? ›
The Optimal Square Feet Per Person For The Ideal House Size
I believe the ideal square feet per person is about 600 – 700. This means for a family of three, the ideal house size is 1,800 – 2,100 square feet. For a family of four, the ideal house size is between 2,400 – 2,800 square feet and so forth.
How to determine the square footage of a house? ›
If the property is a perfect rectangle, simply measure the length and width and multiply those two numbers together. For example, if your one-story house is 60 feet wide by 40 feet long, then your property is 2,400 square feet (60 x 40 = 2,400).
What document shows the square footage of a house? ›
Any square foot source other than the county must be documented — by a builder's floor plan, an appraisal, an official floor plan (there are companies that do this for a fee), etc. The county's measurement is the only one that does NOT require additional documentation.
Where can I find the square footage of my house online for free? ›
You should be able to check with your city or county's Assessor's office. Often this information is available online through their websites. This official info is what your taxes are based on, so is probably the best "official" number for what your house square footage is.
What is the correct formula for calculating area? ›
The formula varies depending on the shape. For rectangles and squares, A = length x width. The area of a circle is A = 𝜋r^2. Finally, the area of a triangle is A = ½ (base x height).
What is the rule for calculating area? ›
Area Formulas
Area of a rectangle is the length times the width. Area of a parallelogram is base times the height. Area of a trapezoid is one half the sum of the two bases times the height. Area of a circle is π times the square of the radius.
Calculating area of land with 4 unequal sides would require you to first, sketch out the land using the dimensions provided. Then make an appropriate diagonal. Next, determine the areas of the two triangles that the diagonal creates. The size of the land is calculated by adding the areas of the two triangles.
How to calculate square feet from length, width, and height? ›
How to calculate square footage. To calculate the square footage of any area, all you need to do is multiply the length and the width of the area (how tall x how wide).
What is the formula for calculating square feet? ›
The next step in how to calculate square footage is to plug your measurements into the square footage formula: L x W = A (in square feet). How to find square feet: multiply the length measurement in feet by the width measurement (in feet).
Is there a tool that measures square footage? ›
Moasure is an incredibly smart measure, working powerfully with all the data it collects. Touch the diagonal corners of a room and Moasure will produce length and width measurements and calculate the 2D area of the room all at the same time.
How do I find the square footage of a house? ›
Calculating the square footage of your property involves measuring the length and width of each living area, and then multiplying these figures together to get the area in square feet. This process should be repeated for all rooms or sections of the house, and the results summed up to get the total square footage.
How do I figure out the size of my house? ›
Measuring Your House
The best way is to go outside and measure the length and width of your house and multiply those figures together. If you cannot measure outside, measure inside and add the thickness of the walls. You can measure either in feet or metres. An integral garage would be included in this calculation.
How to calculate the built-up area of a house? ›
As per RERA, the built-up area includes the carpet area plus the extra areas certified by the authorities, such as the area of the outer and inner walls, dry balcony area, etc. Built-up area calculation: Carpet area + wall area + excluding balcony and corridor = Built-up area.
What size house sells best? ›
Last year, homes in the top 1% by price nationwide that measured between 5,000 and 10,000 square feet were on the market for an average of 97 days before selling. Homes measuring between 2,000 and 5,000 square feet, by contrast, took 102 days to sell, and homes larger than 10,000 square feet took 126 days.
What size house is considered big? ›
An average home is in the 2,500-square-foot range. Large homes are 4,000 square feet and bigger.
Is 1500 sq ft a small house? ›
For many, a 1,500 square foot house might seem like a small home, but you can still fit in 2-3 bedrooms, making it the ideal house for a couple or small family.
As for rooms in the house that aren't finished, like basem*nts or attics, they should not be included in the total square footage. In fact, any part of the house that is below ground level -- even if it is only partially so -- should not be included under any circ*mstances.
What areas of the structure are not included in the square footage calculation? ›
Spaces like garages, three-season porches and unfinished basem*nts or attics are not included in the square footage of a house. But if a basem*nt or attic has been “finished,” then the space may be included in the home's square footage if it also meets ceiling height requirements.
What is not included in net square footage? ›
Net Square Footage (NSF)
Note: NSF calculations do not include wall thickness or space that is open to below.
What parts of a house are included in square footage? ›
This includes bedrooms (and closets), bathrooms, hallways, a kitchen, living areas, enclosed patios, and finished attics. Unfinished areas, screened or open patios, vaulted rooms, and airspaces are not factored into a home's square footage.
