How Many Square Feet Is My House? How To Calculate The Square Footage Of A House

How Many Square Feet Is My House? How To Calculate The Square Footage Of A House

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 basement 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.


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.

  • 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.
  • 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.
  • 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.

How To Measure Square Footage Of A House In 3 Steps

To calculate the square feet of a house, you will need to determine each room’s area and add it together. It sounds easy, right? We’re going to try to keep it that way as we walk you through the process. Gather a few tools before getting started:

  1. Tape Measure

  2. Notepad and pen/pencil

  3. Calculator

You may also want someone to assist as you measure, especially in larger rooms. While it all depends on the shape of your house and the complexity of your floor plan, sometimes it’s a good idea to start this endeavor with a helping hand. When you are ready to get started, there are three steps to follow:

  • Measure the length and width of each room and hallway in your house.

  • Multiply the length and width of each room separately, which you can write down before your final calculations.

  • When you are done measuring and multiplying, add the area of each room together.

Square Footage Of A House Example

For example, pretend you live in a ranch home in the shape of a rectangle. The length of the house is 70 feet, and the width is 50. This means to calculate the square footage, you will multiply 70 by 50, resulting in a final calculation of 3,500 square feet. Of course, not every home is a perfect rectangle — making it more time-consuming to get accurate numbers. That’s why going room by room is often the most practical method. With the proper measurements and some addition, you can still calculate the square footage of your home.

When does an attic count as finished square footage?

Some people wonder if an attic can be included in the finished square footage of a home if there is a pull-down ladder or existing stairway to the space. To be included in the square footage, an attic would first need to meet the same criteria as any other space — heating, flooring, ceiling and wall covering. It would also need to be accessible by a conventional stairway.

But what about non-traditional floor plans, like a 1.5-story layout common in older homes? Or a four-level split floor plan? The second level of a 1.5-story home often can be included in the finished square footage count, but only if the ceilings are of sufficient height. For example, in some MLSs the ceiling must be at least seven feet at the highest point. Spaces where the ceiling is less than five feet tall must be excluded entirely from square footage.

Hire a Professional to Measure the Square Footage of a House

That seems like a lot of work, you’re saying to yourself. The good news is that you don’t actually have to do it yourself. In fact, you shouldn’t, at least not in an official capacity. It’s nice to be able to estimate, double check and generally know what counts and what doesn’t, but when it comes to putting your house on the market, it’s important to get a professional.

Angelina Keck, a top-selling agent who ranks in the top 1% of agents in Houston, says you should call an appraiser and ask for a measure. It’ll cost you about $150. “They’ll put their stamp on it so it’s official. This is the best and most reliable way to estimate square footage.” An appraiser will likely take measurements from the exterior.

You should hire an appraiser to measure because:

Source: (Sergey Zolkin/ Unsplash)
Source: (Sergey Zolkin/ Unsplash)

You might count something that doesn’t count

Square footage gets a little murky. Areas like your patio, your garage, your basement and your attic… even though they are clearly parts of your home, are not necessarily considered part of your “gross livable area” (GLA). There are some exceptions to this though.

  • Your garage doesn’t count as part of your square footage.
  • If your attic has seven feet of ceiling clearance and it’s finished, you can count it.
  • A good litmus test for whether an area counts as GLA is whether the room is heated or cooled by the same means as the rest the house. If your house is on central A/C but your enclosed patio has a swamp cooler, you can’t count the patio in your square footage.
  • Basements are only sometimes counted. It depends on the area, as well as if it’s finished or not. (Is it mostly old boxes, or does your son live down there?)

Say you measured everything yourself and you tell your Realtor that your house is 2,200 square feet. She puts this into MLS. It’s highlighted on your house flyers. It’s plastered across the internet. Eventually, someone puts in an offer. But during the vetting process, their appraiser comes up with a lower number — only 1,600 square feet. Uh oh.

You counted your giant garage in your measurement and now the sale could fall through because their offer was based on a 2,200-square-foot house. A good agent will look for that appraiser stamp, but it’s still good to look out for yourself too.

You can’t always depend on tax documents

Why pay to have someone measure when your tax documents already have your square footage? Because you can’t always trust what they say. When builders make plans, they send them to the county assessor. As a development sells (or doesn’t), builders and architects may make adjustments to those floor plans but they don’t necessarily update the city. This means tax reports sometimes reflect the wrong square footage for houses.

You might already have all the information

Don’t sign up for more work than you have to. If this isn’t the first time your home has sold, someone had to have an appraiser measure the last time it sold. Locate that report. Unless you constructed an addition, that appraiser stamp on the measure is still accurate and valid.

How to calculate the square footage of a house: Three steps to follow

As a buyer it can be helpful to know how to calculate the square footage of a house yourself – just multiply the length and width of all applicable rooms in the home. All you’ll need to get started is a 100 sq ft tape measure, some graph paper, and a pencil. 

1. Assign a unit of measure

Assign a unit of measure to each square on the paper (ex. 12 inches or a foot) and measure to the nearest tenth of a foot.

2. Pick a wall

Pick a wall and begin measuring the distance, making your way around the interior perimeter of the house in one direction, then drawing lines accordingly on the graph paper. Keep in mind that although ANSI guidelines specify measuring the exterior walls, measuring from the inside will give you a better idea of the actual livable area.

3. Look at your floor plan

Lastly, go back over your floor plan, multiply the rectangular areas, and add them all up to get your final number. If your calculation includes an area that is not permissible, don’t forget to subtract it out.

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.

Basements and garages, even if they are finished, don’t generally count toward total square footage. Basements are typically excluded because they are built below grade, meaning below ground level. If your state does allow basements 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 basement 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.


Count only those areas that are “inhabitable” according to ANSI standards. Inhabitable portions of a house include rooms with walls, ceiling and floor. These areas must be finished and heated or otherwise conditioned. Do not include spaces like patios, porches or garages. Also, if the house has an area with a vaulted (two-story) ceiling, do not count the open area as part of the second-story square footage.

How to Calculate Square Footage

Square footage is area expressed in square feet. Likewise, square yardage is area expressed in square yards.  Square meters is also a common measure of area.

Assume you have a rectangular area such as a room and, for example, you want to calculate the square footage area for flooring or carpet.

The way to calculate a rectangular area is by measuring the length and width of your area then multiplying those two numbers together to get the area in feet squared (ft2). If you have on oddly shaped area, such as an L-shape, split it into square or rectanglualar sections and treat them as two separate areas. Calculate the area of each section then add them together for your total. If your measurements are in different units, say feet and inches, you can first convert those values to feet, then multiply them together to get the square footage of the area.

Convert all of your measurements to feet

  • If you measured in feet skip to “Calculate the Area as Square Footage”
  • If you measured in feet & inches, divide inches by 12 and add that to your feet measure to get total feet
  • If you measured in another unit of measure, do the following to convert to feet – inches: divide by 12 and that is your measurement in feet – yards: multiply by 3 and that is your measurement in feet – centimeters: multiply by 0.03281 to convert to feet – meters: multiply by 3.281 to convert to feet

Calculate the Area as Square Footage

  • If you are measuring a square or rectangle area, multiply length times width; Length x Width = Area.
  • For other area shapes, see formulas below to calculate Area (ft2) = Square Footage.


Knowing how to calculate square feet of houses is beneficial to you. Knowing how to do this will help you when it comes time to sell your home, plan for projects, and appeal a property tax assessment.

All interior parts of your home are included so long as there is a floor you can walk on. Parts of your home that do not count are garages, unenclosed outdoor areas, accessory structures, crawl spaces, or unfinished attics. Make sure to classify each portion of square footage as finished or unfinished, too.

You can find the square footage of a house by measuring each room. Think in squares and rectangles to make measuring easier. There is nothing wrong with measuring a living room with a bump out as two pieces to make it easier. Figuring square feet is easier with some basic tools you likely already have, too. Now, you are ready to find the square footage of your home.

Ready to purchase?

When it comes down to it, the square footage of a home is just a number. The most important things to consider when determining if the size of a house is right for you are:

  • If you feel comfortable in the space.
  • If the rooms can accommodate your needs.

But, if the numbers are important to you, talk to Edina Realty or your agent for additional help. We are available to connect you with an experienced agent seven days a week.

For more tips on buying a home, follow #BuyerInsights on Facebook, Twitter, YouTube and Instagram.


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