How to Calculate the Square Footage of Your Home

Understanding how the square footage of a house is measured

To understand how the square footage of a house is measured, start by referring to your city’s building department records. Many city and county records are now available online, which makes getting this information much easier than it used to be. Some updates – like unpermitted remodeling – may not be reflected in the records, but it will still provide a good baseline estimate.

Then, familiarize yourself with basic ANSI guidelines for calculating square footage for single-family homes. Practices can vary slightly from market to market, but these rules apply to most areas in the country:

  • Below-grade spaces (basements, dens, etc.) do not usually count toward a house’s square footage. Even a finished basement oftentimes can’t be counted toward a home’s Gross Living Area (GLA), but it can be noted separately in the listing’s total area. More on this below.
  • The ANSI method specifies measuring from the exterior of the house, but the wall width is not usually subtracted to account for actual living space.
  • Stairways and closet areas are included in the house’s square footage length.
  • Finished attic square footage is included if an area has at least seven minimum feet of clearance.
  • Covered, enclosed porches can only be included if heated and using the same system as the rest of the house.
  • Garages, pool houses, guest houses, or any rooms that require you to leave the finished area of the main house to gain access are not counted in the square footage of a house.

Why is the accurate square footage of a home so important?

A home’s value is predicated on a number of factors, and while square footage is just one of them, it’s an important one.

“The value of your home is directly tied to the square footage,” says Henley. “During the sale process, the appraiser will measure your house. If you have marketed the home with the incorrect square footage, that can come back to get you when the appraisal comes in.”

Consider what would happen if the appraisal comes in and reveals the home is smaller than what you were marketing it as. In this case, the appraised value may come in lower than the sales price, creating an appraisal gap and putting the buyer’s mortgage approval in jeopardy, and you may have to lower the price to account for the lower square footage.

In contrast, “If you’ve been marketing in the house smaller than the appraiser finds, then you’ve cost yourself money,” says Henley. “The sales price could have been higher.” Incorrect square footage can also affect the time it takes to sell the property.

Henley shared a story wherein a seller’s home had been sitting on the market for quite a while. The homeowner reached out to Henley for help. When Henley showed up and measured the house, he found that it was 400 square feet less than what was listed because the seller had included an area that didn’t count toward the GLA. Once the square footage was adjusted and the price lowered, the property sold in a week.



What is included in the square footage of a house? Most spaces in the home are included in its square footage, including stairways, hallways, and closets. Finished attics will be included if they have at least seven square feet of clearance. Covered and enclosed porches can also be included if they are heated using the main HVAC system. However, basements or other below-grade spaces are not counted toward a home’s gross living area (GLA), nor are any areas that require you to leave the main finished area of the house, such as garages, guesthouses (casitas), or pool houses.

How does an appraiser determine the square footage of a house? Most appraisers use a simple technique to determine gross living area (GLA). They measure the exterior of the home. If the exterior measures 30 feet by 40 feet and is one story, the home contains 1200 square feet. This includes all closets, hallways, stairwells, and even wall space since its starting from the exterior. The appraiser will also take into consideration other finished spaces not included in the square footage but usually at a lower price per square foot than the main house.

Does square footage of a house include all floors? Square footage of a home includes all above-grade floors, usually excluding basements. An attic can be included if there are at least seven feet of head clearance and HVAC.

Are hallways included in square footage? In the gross living area (GLA) calculation, an appraiser (or someone else) calculates square footage by measuring from the outside, so wall space, stairwells, and even hallways are calculated in the total square footage.

Do closets count as square footage? Yes. Closets are considered a part of the home’s gross living area. Measure the area of the closet just like any room and include it in the total square footage.

Does square footage include the garage? No. Garages are not considered a part of a house’s gross living area. However, you can still mention in your listing that your house includes a garage.

How much does an official appraisal cost? The average is between $300 and $400, but it depends on where you live, how big your house is, and other factors. The range is from $250 to nearly $500.

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.

Why square footage is important

Square footage has a big impact on listing price. Usually, agents will determine the price to list your home for by comparing it to the list price of homes of a similar size in your area.

Of course, other factors will play a big role as well — including whether rooms that don’t count toward your gross living area (GLA) — have been renovated. But square footage is a useful starting point for estimating how much you can sell your house for.

List price isn’t the only reason square footage is important. Property taxes are often tied to home size. If your local land records office has an incorrect measurement of your home’s square footage, you could inadvertently be paying too much in taxes.

Also, if you want to carry out a major renovation or build an extension to your house, you may need to get a building permit. In many cases, you’ll need to provide the square footage of your house to get a permit.

4 Tips for Determining Square Footage

Here are few things to consider when preparing to measure the square footage or a property:

  1. 1. Draw A Floor Plan. Make a rough sketch of your property's floor plan. This will give you a sense of how you’ll add your calculations for each room together. This is an especially important step if you’re measuring irregularly-sized rooms with a square footage that involve a little more calculation.
  2. 2. Plan which rooms you will be measuring. When calculating square footage in any home, you should include the measurements of all the rooms in your house that are “finished,” enclosed by four walls, and are heated or cooled. You can measure spaces like garages, basements, or outdoor spaces for your own knowledge, but they should not be included in your square footage calculation.
  3. 3. Take extra care with irregularly-shaped rooms. All you need to do to measure the square footage of square or rectangular areas is multiply length times width. However many rooms in a home will be more oddly shaped. To determine the square footage of irregular rooms, measure the length of each wall using a measuring tape and record the dimensions on your floor plan. Then divide the shape of your room into regular shapes like squares, triangles, or circles. Calculate the square footage of each separate shape and add them together to get the total square footage of the room.
  4. 4. Remember the stairs. Include stairs in your home’s square footage calculation if you have them. Multiply the depth and width of one stair, then multiply that number with the number of stairs you have. Some appraisers will include the square footage of stairs twice, as they are considered a part of the floor plan of the floor from which they are descending and the floor to which they are descending. There are no standards governing whether you should include your stairs square footage twice.

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.

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.

Using the Information

If you’re satisfied the homes are genuinely comparable to one you want to sell or buy, look at the sale prices. You want yours to be competitive with similar homes – going ultra-high can hurt you, and pricing really low might lose you money. If you’re disputing your property tax assessment, you’ll need to use your assessor’s appeals process. At some point, you’ll present the comps as evidence that your tax bill is too high compared to what the neighbors are assessed.

Read More:How to Get a Retrospective Home Appraisal


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