How to Calculate the Square Footage of a House

4 Steps for Measuring the Square Footage of a House

If you’re measuring square footage to find out how much livable space your house has, you’ll want to take interior measurements. By measuring from the inside wall, you can get a better sense of whether or not the space meets your needs. For example, you might have a sofa that needs a certain length of wall space. If the room doesn’t have it, the sofa won’t fit.

The steps for calculating the square footage of a house are:

  1. Sketch each room of your house. Plotting out every room of your house, including hallways and closets, can help you tally your square footage as you go
  2. Measure the length and width of each room. Use a measuring tape to measure the length and width of every room in feet. This is easy when the room is rectangular or square. However, if you have oddly shaped rooms, you may want to use a square footage calculator .
  3. Multiply the length and width. For example, if your living room is 20 feet by 15 feet, its square footage is 300 square feet. Note each room’s measurement on the sketch you created in the first step.
  4. Add room values together. Take the totals from each room and add them together to get the total square footage of the house. This is the usable space in your home and may be different from an appraisal or the country tax records.

If you have a room with nooks and crannies you may need to break it down into measurable rectangles. That way, you can get the square footage of the smaller spaces and add them all together for the room’s total square footage.

For example, let’s say that your living room is 10-foot wide, but one wall has an odd notch at the corner that protrudes one foot into the room, like the image shown below. The best way to measure the square footage for tha

The best way to measure the square footage for that room is to divide it into two rectangles. The first rectangle starts at the edge of the notch and goes to the other wall, and the second is the rest of the room.

Some people make the mistake of calculating the square footage of a two-story home by measuring the bottom floor and simply multiplying that number by two. This can be accurate if the floor plans for each floor match exactly, but it’s incorrect for homes with two-floor entryways.

How is Square Footage of a House Calculated for an Appraisal?

Most people who buy a house get an appraisal to determine its fair market value, and one of the appraiser’s tasks is calculating the home’s square footage. The process is often similar to what you would do to measure square footage. However, your appraiser’s calculation might not match yours or even what’s on the actual listing.

The most common reason the square footage may be different in your appraisal is because an appraiser needs to evaluate the total value of your home. As a result, the square footage in an appraisal may include nonliving spaces, like attics, unheated basements, and open patios.

Your appraiser’s square footage calculation may more closely match what’s on county tax records, but that’s not always the case. For example, the square footage of a house may not be accurate on tax records if the owner enclosed their patio without getting permits.

Is House Square Footage Measured Inside or Out?

Whether a home’s square footage is measured by the interior or exterior depends on who you ask. An interior designer and realtors who need to determine the usable space may use the interior walls. Architects, however, may use exterior walls.

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.

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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.

Conclusion

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.

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.

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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.

Summary

Those that know how to find the square footage of a house carry an inherent advantage in every deal they work on. Of particular importance, however, is accuracy. Those who can accurately learn how to calculate square footage of a house stand a better chance of realizing success. At the very least, they will know exactly what they are getting into (or out of).

Have you ever run into questionable home measurement calculations? Would it have helped if you knew the standards used today? Please feel free to let us know in the comments below.

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