Tips For Calculating Square Footage In A Home

Key Takeaways:

Whether you are calculating square footage in your own home or a real estate deal you hope to acquire, confirming the amount of space a property has (or doesn’t have) isn’t optional but rather necessary. At the very least, it is in your best interest to know exactly what you have at your disposal. Perhaps even more importantly, learning how to calculate square feet of a house can prove incredibly beneficial if you want to list your own property or confirm the numbers provided by any sellers you may be working with.

Why Do You Need To Calculate Square Footage?

There are several reasons why you may need to calculate square footage. Think about the last time you purchased a property: what information did you look at on the property listing? More often than not, the square footage was one of the most important numbers. Square footage is crucial when looking for properties — and as an investor knowing how to calculate it can help you estimate the sale price of a home. Lenders will also be interested in the square footage to ensure the purchase price lines up with the property value.

Square footage is also important when it comes to property tax evaluations. It is crucial to get the size of your home right to avoid overpaying from year to year. If you think your city has incorrectly evaluated the square footage, calculate it for yourself before requesting a new assessment. Similarly, if you want to complete any renovations or additions to your property, you will need the square footage to get a permit from your city. It is always a good idea to consider how renovations will impact your property’s size, whether you plan to sell or keep it.

If for nothing else, understanding how to calculate square footage can serve as one more tool in your investor toolbox, one that may give you the edge you need. You should keep in mind several tips if you want to become more proficient in calculating a home’s square footage.

Can I Measure The Square Footage Of My Home?

It is entirely possible to measure the square footage of your own home, but it’s a task that shouldn’t be taken lightly. While it’s easy to assume measuring a home’s gross living area (GLA) is as simple as adding some numbers together, there is a lot that must be accounted for and, quite frankly, a lot that can’t be added to the total square footage of a home. That said, those looking to calculate the amount of “usable living space” in a respective property have two options: hire a professional or abide by the standard set forth by the American National Standards Institute (ANSI).

[ Want to create a roadmap to a financially secure retirement? Register for our FREE online real estate class to learn the powerful wealth building strategies real estate investing has to offer. ]

how to calculate square footage

How To Measure Square Feet Of A House

To calculate the square feet of a house, you will need a few supplies: a notepad, calculator, and measuring tape. The simplest example is to imagine your house as a perfect rectangle and multiply the length times the width. If your house is 50 by 30 feet, the square footage would be 1500. Most homes are not a “perfect” shape, and you will likely need to spend some time measuring individual rooms and areas before adding together the overall square footage.

Suffice it to say, there is no universal home square footage calculator. However, the standards put in place by ANSI can make it easier to determine which areas of your home can be added to the square footage calculations and which ones should be ignored. For the most part, you should include all livable spaces, excluding basements, garages, or attics. It can help start by looking at a floor plan of your property and measuring from there. Look for rectangles and try to break up each room or hallway. The tips below should help as you learn to calculate square footage correctly.

[ Ready to take the next step in your real estate education? Learn how to get started in real estate investing by attending our FREE online real estate class. ]

Tips For Determining Square Footage Correctly

The process for determining square footage does not have to be as complicated as it seems. Read through the following tips for help getting started:

  1. Height Requirements: Most people are surprised to learn that height is an important indicator when calculating a home’s square footage. That’s not to say you measure a 3-D space, but rather that the height of a room will tell you if you can add it to the home’s GLA. In other words, ceilings must be a certain height to count that room’s square feet in the usable living space equation. 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 may be 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.

  2. Garages: Regardless of whether or not the garage is “finished,” it may not be added to a home’s total square footage. That’s because most garages aren’t on the same level as the rest of the property; they are typically lower. Below grade areas (like garages) that require you to leave a finished room are not up to ANSI standards and are, therefore, not to be included in the GLA calculation.

  3. Protrusions: Protrusions — like chimneys and windowsills, for example — are not included in a home’s square footage calculation. Not unlike the garage, these features are not on the same level as the rest of the home; they are slightly elevated.

  4. Finished Vs. Unfinished: For the most part, unfinished areas of the home are not included in a home’s total square footage. To be included, the area must be finished. You can list unfinished areas — like basements, such as unfinished bonus spaces, as long as you leave them out of the overall finished square footage calculation.

  5. Home Additions: Home additions may be included in a home’s square footage, but only if they are finished and connected to the home by a finished transition (finished staircase or hallway). That said, the addition may not be included if the hallway or staircase isn’t finished.

  6. Basements: Regardless of whether or not they are finished, basements do not typically count towards a home’s gross living area. 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.

  7. Attics: Attics, on the other hand, have the benefit of being above grade. That means they can be included in a home’s square footage if they meet two requirements: they are finished and meet the height requirements specified above.

  8. Covered, Enclosed Porches: Covered and enclosed porches, not unlike a California Room, can be included in the square footage of a home if they are finished, and they are heard by the same heating system that heats the rest of the home. To be clear, it doesn’t need to have air conditioning, but it does need heat.

how to calculate square footage of a house

Is Calculating Square Footage For Insulation Different?

The answer is unequivocally yes. Namely, because the calculations promote two different indicators. Not surprisingly, insulation square foot calculators are typically used to determine a home’s sustainability. To be considered efficient, a home must have sufficient insulation in both the attic and walls. On the other hand, the gross living area has much less to do with efficiency and more to do with usable living space. It is worth noting, however, that larger numbers in both calculations tend to lend to more valuable homes. So while calculating square footage for insulation is different, it could be worth your while to make sure your home has a sufficient amount of insulation. That way, you can market your home as both green and efficient.

Hiring A Professional

Accurately calculating square footage is essential for determining the value of your home and the correct size before any renovations can be made. That being said, you may want to consult professionals if you have any doubts about your calculations. A professional appraiser can be hired for as little as $100. You can get measurements from two different appraisers who will calculate square footage between a 1 to 3 percent variance for even more accuracy.


There is no doubt in my mind: knowing how to calculate square feet of a house is of the utmost importance. At the very least, it will give you a more accurate picture of the home you are either living in or intend to buy. That said, there’s really no excuse for not calculating a home’s total square footage — not if it can help you sell your home for more or acquire one for less.

Have you ever had to calculate the square footage of a home? Have you ever been given false statistics on a home’s gross living area? We would love to hear if you could benefit from knowing how to calculate home square footage in the comments below.

Want to learn how to take advantage of the current opportunities in the real estate market?

Whether you’re brand new to real estate or have closed a few deals, our new online real estate class covers everything you need to know to help you get started. Expert investor Than Merrill explains the best real estate strategies for today's real estate market to help get you on the path towards a better financial future.

Register for our FREE 1-Day Real Estate Webinar and get started educating yourself on how to invest in today’s real estate market!

Real Estate Investing Strategies
Real Estate Investing Strategies
Real Estate Investing Strategies
Real Estate Investing Strategies
Real Estate Investing Strategies
Real Estate Investing Strategies