How to Calculate the Square Footage of a House

Single-Story Homes

  1. 1

    Draw a picture of the home’s outline on a sheet of paper. Single-family homes are easier to measure outdoors. Just the length and width of the home need to be measured.

  2. 2

    Place the tab of the tape measure on one corner of the home and pull it until you reach the opposite side. This task is easier with two people, one to hold the tab in place and the other to measure the length of the wall. If your tape measure isn’t long enough to reach the other side, make a small mark with the pencil on the wall and write down the measurement up to that point on the paper drawing of the home’s layout.

  3. 3

    Repeat these steps until the length and width of the home have been noted. Add up the feet of the two wall spans separately, and round any fractions up to the next inch. Convert the measurement to feet for both walls. Multiply the length by the width, and the product will indicate how many square feet are in the home.


Why Is Square Footage Important?

Square footage is important in real estate because it is the clearest representation of the total area of livable space in a homeowner's property. Here is an overview of the practical reasons that square footage is important.

  • 1. Home value: Square footage is one of the variables factored into setting the listing price or determining the fair market value of a house. If you order an appraisal for your new house to determine its fair market value, the appraiser will factor the square footage of this house to similarly-sized homes in the area.
  • 2. Securing a mortgage: Most mortgage lenders will require homebuyers to get a home appraisal before granting them a loan to protect the lender from promising more money than the house is worth. If your appraiser finds that a home is worth less than it is listed for—potentially because of a square footage discrepancy—the buyer may not get a loan for the house unless the listing price is adjusted to affect the appraisal value.
  • 3. Property taxes: Assessing your home and measuring the square footage can help gauge whether a homeowner is paying too little or too much in property taxes. Your property’s square footage directly impacts the assessed value of the house, which influences property taxes you’re required to pay.

Who should measure the square footage of my house?

As of April 2022, Fannie Mae, a government-sponsored enterprise (GSE) that buys mortgages from lenders, requires that appraisers follow the Square Footage Method for Calculating: ANSI® Z765-2021. While this standard can’t be followed when measuring apartment-style condos, Fannie Mae requires it for any non-apartment-style residence. This includes townhouses, rowhouses, and single-family homes.

Because Fannie Mae purchases about half of all mortgages that lenders make, the criteria that lenders have for their loans typically conform to Fannie Mae standards, which now include having an appraiser measure a home’s square footage, compliance with the ANSI standard, and a computer-generated rather than a hand-drawn sketch.

Keck also recommends hiring an appraiser to measure the square footage. It’ll cost you about $300 to $400, and “they’ll put their stamp on it so it’s official. This is the best and most reliable way to estimate square footage.”

How to calculate the square feet 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.

  1. 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.”
  2. 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.
  3. 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.

How To Measure Square Footage Of A House: FAQ

There is a lot of confusion surrounding the square footage of a home, likely because of misinformation and a lack of well-known guidelines. That being said, if something seems unclear, more often than not, someone has probably wondered the same thing. Below are some commonly asked questions about how to measure the square footage of a house.

Finished Vs. Unfinished

Generally speaking, unfinished areas of the home are not to be added to its total square footage. To be included, the area must be finished. For example, you can list unfinished areas — like basements — as unfinished bonus spaces, as long as you leave them out of the overall finished square footage calculation.

Are Basements Included In House Square Footage?

Basements have become the subject of many heated debates surrounding a home’s square footage. At the very least, the answer is, well, yes and no. You see, basements — whether they are finished or not — should not be considered in a home’s total square footage, according to ANSI. That said, it is completely acceptable for homeowners to list the size of their finished basement in a separate part of the listing (separate from the home’s actual gross living area). So while today’s standards advise against adding the square footage of a finished basement to the home’s GLA, there’s no reason you can’t include the actual size of it somewhere else in the listing.

[ Want to maximize your property value? Download this step-by-step guide to making “high-ROI” home improvements. ]

Does House Square Footage Include Garage?

Whether it’s finished or not, a home’s gross living area does not include the garage. According to ANSI, “garages and unfinished areas cannot be included in the calculation of finished square footage.” Most garages can’t count towards the square footage of a home because they are not typically on the same level as the home; they are usually lower.

How Many Square Feet Are In The Average House?

The average house has about 2,400 square feet. According to the U.S. Department of Housing and Urban Development, the average square footage in 2017 was 2,426 square feet. In contrast, the average square footage was 1,660 in 1973. The number has steadily increased over the decades, reflecting Americans’ desire for more rooms and larger homes.

What Is The Square Footage Of A 12 X 12 Room?

A 12 X 12 room has 144 square feet. Simply put, square feet are calculated by multiplying the width by the length of a given room. Each room is then added up to get the total square feet of a house. Things can get complicated with add ons and other features that take away space from rooms. A good way to overcome any structural issues is to break each room into squares. Look for where walls line up and divide things in a way that makes square footage easier to calculate. You can then add up your smaller numbers to get a more accurate total.

Do Closets Count In Square Footage?

Closets do count in square footage, so long as they meet requirements applied to other areas of the house. What I mean by this is as long as closets are finished and meet the ceiling height requirements I mentioned above, they will count towards total square feet. The same logic can be applied to stairways, which are another gray area for calculating house square footage.

Total Area Vs Living Area

The total area refers to the full amount of space in a property, while the living area only includes rooms that rely on the main heating and air system. Living area is essentially another way to say square feet. On the other hand, total area will include garages, basements, balconies, and any other spaces that fall under the same roof. It is not uncommon to see both measurements given in a property listing or during an open house.

What Is Considered Livable Square Footage?

Livable square footage includes any room or space that uses the main heating and air system in a property. This includes bedrooms, bathrooms, closets, and more. The exact definition of livable square feet may be different from state to state. However, as a general rule, livable square footage refers to usable, heated spaces in a property. Keep this in mind as you calculate your house’s square feet, and ask a realtor or appraiser if you are unsure of your estimates.

Expert tips about your home’s square footage

What is the biggest misconception sellers have about a home’s square footage?

Henley emphasizes that square footage is just one of the many factors that go into pricing a home. “The four big factors of pricing a home are location, condition, marketing, and price. So I really try to get my sellers to recognize that square footage is important, but it’s no more important than how clean your house is or how nice the landscaping is,” he says. It’s just one of the many, many factors that go into pricing the home.”

Ultimately, he says, “It’s not as simple as calculating the square footage, multiplying by $150 and, boom, you’ve got the price.”

Another misconception, according to Henley, is that more is always better. He has seen instances where clients have converted their garage into a living space. They gain square footage in the form of more heated and cooled space, but they lose the garage. So while a garage doesn’t count toward the total square footage it will likely positively affect the value of a home.

Can I hire a professional to measure my home’s square footage

You can hire a professional to measure your home’s square footage and, in fact, you should. The buyer’s lender will likely order an appraisal through an appraisal management company (AMC) after their offer is accepted, and if the appraiser finds a discrepancy in your measurements and theirs, it can cause problems during the closing process. Having a professional measure the home prior to listing it can reduce the likelihood that problems will arise later.

Can I just use the square footage listed on my tax documents?

Henley cautions against using your tax documents to determine the square footage of your home, saying “The problem with tax records is they measure from the outside, but they don’t go inside to check for dead spaces, they don’t go into the garage to check to see if there’s a big garage storage room. So tax records are never really accurate.”

Are there other sources that might already have accurate home measurements for my home?

If your house has sold before, then it was probably measured by an appraiser the last time that it sold. This isn’t always the case as some cash buyers don’t order an appraisal. If it was measured, you can locate that report and use it as a jumping-off point, but you may still want to have an appraiser measure to ensure that the measurement is accurate and complies with ANSI standards.

If you live in a townhome, condo, or tract home, the original architectural drawings or plans may also show your home’s square footage.

How Important is Square Footage of a House?

Square footage can be very important when it comes to buying or selling a home. Many buyers start looking with a particular number in mind, so having an accurate measurement can help get your home in front of the right audience.

However, Chief Real Estate Analyst and Managing Editor of The Close , Emile L’Eplattenier says that in some cases, other features can be more important than square footage. A good example in some markets is when developers decrease size in favor of amenities.

“While price per square foot is still a useful metric,” says L’Eplattenier, “developers of luxury buildings in Manhattan and Brooklyn have been decreasing average unit sizes for more than a decade now.”

Ultimately, homebuyers need to use the square footage of a house they’re interested in as one piece of information. It may tell them something about whether the house fits their needs, but they need to weigh other factors, like location and quality.

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How To Figure Square Feet For Your Home

Calculating the square footage of a home is relati

Calculating the square footage of a home is relatively easy. To measure square feet, you just have to take it one room or space at a time. Measure the length, measure the width, multiply these two and you have the square footage of a space. For example, let’s say a bedroom in your home is 12 feet wide by 14 feet long. 12 X 14 = 168, so that bedroom has 168 square feet.

With one extra step you can easily measure square footage for odd sized rooms that do not end on a specific foot measurement. Let me show you how by slightly adjusting the example I used above.

Let’s say that bedroom is 12 feet 9 inches wide (or 153 inches) and 14 feet 9 inches long (or 177 inches). Notice what I did here. Ignore the foot measurement on your measuring tape all together. Instead, only look at the total inches for length and width. Here is the math with the extra step:

  1.  Divide each inch total by 12 (153 divided by 12 is 12.75 and 177 divided by 12 is 14.75)
  2. Multiply the two numbers (12.75 x 14.75)
  3. Answer: 188, the room is 188 square feet

What is included in square footage of a house?

The easiest way to calculate square footage is to measure all areas and rooms with a floor. If you can walk on it it counts. Square footage includes all of the spaces in your that is actual space. Your square footage total should include:

  • Bedrooms and the closets
  • Bathrooms
  • Hallways
  • Kitchens
  • Living or recreation rooms
  • Enclosed 3-season or all-season rooms
  • Unfinished spaces like a basement

Garages, outdoor areas, and unfinished attics do not count as square footage.

Finding the square footage of your home

To determine the square footage of you need some basic tools and to follow a few steps. The tools needed include:

  • Pencil
  • Paper
  • Measuring tape

Follow these steps to accurately measure the square footage in your home:

  1.  Measure every space except the garage, the crawl space, and the attic if it is not finished.
  2. Measure at the floor.
  3. Squaring off spaces is often the most practical way to capture all of the square feet.
  4. Multiply the length and the width of each space you measured.
  5. As you measure each space label each space as finished or unfinished and whether it is above grade or below grade

If you are shopping for a home to purchase, the square footage number you see in the listing or online is most likely the total finished square footage. However, it is important to know how much unfinished square feet is present and how much square footage is above grade or below grade. Each of these affect a home’s value.

Finished Vs. Unfinished Square Footage

Many people are confused about are basements inclu

Many people are confused about are basements included in square footage. The answer is yes, basements are included in square footage. However, that square footage should be further classified as finished or unfinished.

Finished square footage is most often defined as a space where the walls, ceiling, and floor are all covered. What does that mean? For walls, it is covered when you cannot see the wall framing. The skeletal structure, electrical and pipes are covered with some other material such as drywall, panelling, or plaster. For a ceiling, this is the same as with walls, you cannot see the skeletal structure because it is covered with some other material.

As for the floor, if you are above the ground, the base material is usually subfloor also known as oriented strand board (OSB). It looks like plywood. If you are in the basement or the home is a ranch on a slab, the base material is likely concrete. To be finished square footage, you should not be standing directly on that material. Instead, there should be some type of floor covering over the concrete or OSB like carpet, hardwood flooring, or tile, or flooring laminate.

When measuring your home to determine its square footage make sure you put each amount of square footage for each room or space into the finished or unfinished column.

Above Grade Square Footage vs. Below Grade Square Footage

Above grade square footage is square footage above the gradient line. The gradient line is where the earth meets the home. Square footage on the main floor and all floors above will almost always be above grade. This only gets a little tricky when the home is a bi-level, tri-level, quad-level, or hillside ranch.

These home models may have a basement, but the lowest level may be called the lower level. This happens because a level of the home is partly under the gradient line but also partly above it. Most areas consider a level like this to be the lower level and mark it as above grade square footage. Check with your local municipality, contractor, or a real estate agent for a certain answer to this question.

Discrepancies in measurement

Because square footage is so vital in appraising a home, it’s important to pay close attention to what is being measured.

Some sellers may include an unfinished basement in their square footage, giving you an inaccurate picture of the livable portion of the home.

And architects and appraisers often calculate square footage by using exterior walls, which may conflict with a property’s GLA figure.

Regardless of how you measure your square footage, be transparent when selling, and diligent when buying.

If you claim that your home is 2,000 square feet based on your builder’s floor plans, and a buyer’s appraiser brings back a figure of 1,600, you could lose the sale or need to lower your price.

Similarly, as a buyer, make sure to do your research and get an independent square footage to ensure you’re getting what you pay for.

Find and claim your home on Zillow to see its recorded square footage and to make edits as needed.


Originally published June 23, 2015.


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