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How To Calculate Square Footage Of A House: A Beginner’s Guide

Written by Than Merrill

The American National Standards Institute (ANSI) established the standard on measuring square footage, but that’s all it is: a standard. For better or worse, the criteria outlined by ANSI are mere guidelines; no official laws govern the true regulation of a home’s gross living area (GLA). As a result, complications arise time and time again as homeowners attempt the process. Learning how to calculate square feet of a house can seem more difficult than many might like it to be.

Fortunately, there is a way for you to make sure your specs are accurate, and it’s in your best interest to learn it. Knowing how to calculate square footage can save you from making some sizable, expensive mistakes.

Why Measure Square Footage?

Homeowners should measure square footage to get an accurate assessment of their property’s size. The most obvious reason homeowners will need this information is for a property value estimation when they sell their house. The square footage will directly influence the purchase price, and it could make a big difference when marketing the property.

Even if you are not selling your home, it can still be helpful to measure square footage. Some cities will require homeowners to disclose this information when applying for renovation or building permits. Square footage can also be helpful in the event your property value assessment comes out too high. In these cases, homeowners will want to accurately re-measure their homes’ square footage to get their property taxes lowered.


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how to calculate square feet from inches

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.

What Is Included In The Square Footage?

In measuring the square footage of a house, it is crucial to know what can and can’t be included in the calculations. Not every foot of your home enclosed by walls will count towards total square footage. Instead, you are trying to determine the gross living area — or the livable parts of your home. Keep reading to learn more about the specifications for measuring square footage:

Height Requirements

There is one measurement far too many inexperienced “appraisers” forget about: ceiling height. That’s not to say you measure the area as a three-dimensional space, but rather that the ceiling is one of the criteria I already alluded to. You see, for an area’s square footage to count in the home’s overall square footage, the ceiling above it must be a certain height. According to ANSI’s American National Standard For Single-Family Residential Buildings, finished areas must have a ceiling height of at least seven feet, “except under beams, ducts, and other obstructions where the height maybe six feet and four inches.” On the other hand, Angled ceilings must rest at the previously discussed seven feet for at least half of the room’s total floor area. If the ceiling is at least seven feet for at least half of the room’s floor area, total square foot calculations should include every area where the ceiling is at least five feet tall.

Garages, Protrusions, and Unfinished Areas

No matter how much you may wish your garage was included in the total square footage of your house, it’s not. I repeat, garages are not included in the total square footage of a property, even if they are finished — that’s because they are not the same level as the home itself. Similarly, chimneys and window areas are not included in a home’s square footage; not only are they not finished, but they are not on the same level.

Finished Home Connections

If you have a finished area connected to the house by a finished hallway or stairway, the subsequent area may be included in the home’s total square footage. However, finished areas connected in any other way (like by an unfinished hallway or staircase, for instance) won’t be included in the home’s total square footage.

Basements & Attics

Basements do not typically count towards a home’s gross living area regardless of whether they are finished. Since they are below the rest of the home, basements can’t be included in the total square footage. That said, homeowners may note the size of a finished basement in a respective listing elsewhere. On the other hand, attics may be counted in a home’s total square footage if they are finished and meet the height requirements stated above.

Covered, Enclosed Porches

Covered, enclosed porches may be included in a home’s gross living area if they are finished, and they are heated using the same system as the rest of the house.


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average square footage of a house

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.

How Do Appraisers Calculate Square Feet Of A House?

Appraisers typically rely on a few different tricks to calculate square footage. After all, this is part of their everyday work. In many cases, appraisers will have a laser pointer that helps them measure each room quickly and efficiently. They can then use these numbers to determine the overall square footage. In a hurry, or a particularly difficult room, they may estimate the measurements.

Other appraisers prefer the old fashioned way, or gathering a tape measure, pen, and paper. As a result of these different methods, some appraisers may have slightly different estimates. Don’t worry though, they are highly experienced at what they do and these minor differences should not negatively impact you.

What Is 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.

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.

What Is 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.

Ask The Pros

Learning how to calculate the square feet of a house can be a challenging task. Thankfully, there are experts to help you. It is common practice to hire a professional appraiser to accurately measure your home. Depending on the property’s size, the cost of an appraiser to measure the square footage can range from $100 to several hundred dollars. When an appraiser calculates the square feet of a house, they also only include areas that are heated and cooled. While two different appraisers will sometimes have different measurements on square footage, there is usually only a 1-3% variance. Appraisers will do their best to calculate square footage with scientific accuracy.

Considering Square Footage When Buying

There are a few critical components to consider before buying a property, and size is one of them. While you can add on to a property, this type of renovation can be costly and challenging to manage without the right experience. In some cases, you may even be limited by the lot size or by building permits. Always consider the ideal square footage as you view different properties. For homebuyers, think about the number of bedrooms and bathrooms and if that meets your needs. Pay attention to the neighborhood, amenities, and more alongside your considerations. You may find the house has the right balance of what you need.

Investors looking to buy a rental property should review other homes in the area. Is the house you are looking at comparably to other units in the neighborhood? The size of the property will directly impact how much you are able to charge in rent, and in turn your return on investment. Consider the average rental price for homes of a similar size and make sure the numbers line up. Square footage should not be the only deciding factor, but it is certainly an important consideration.

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 feet 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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