The square footage of your home — or gross living area (GLA) — is the total area of your home’s floors measured in square feet. Calculating the square footage of your home is relatively simple.
Depending on how quickly you measure each room, you can determine the square footage of your house in an hour or two. However, larger homes or homes with irregularly shaped rooms will take more math (and more time).
Knowing your home’s square footage is essential when it’s time to sell, as it can impact your pricing, taxes, renovation costs, and appraisals.
While owner-calculated square footage isn’t official, these numbers can help you approximate better when gathering estimates from contractors, discussing listing price with your realtor, or setting up an appraisal.
Here’s a quick breakdown of how you can find your home’s square footage:
- Measure the length of two walls of each room that meet in a corner
- Multiply those two lengths together to find that room’s square footage
- Add the square footage of every room together to get your total gross living area
Pro tip: Only calculate heated and cooled rooms above the basement level. These are the areas typically referred to as “livable space.”
If you need your square footage because you want to sell your house, doing it yourself can give you an idea of how much you can list it for.
But the process can get complicated quickly, and listing on the MLS often requires a professional measurement.
One reason for the complication is that there is no national standard for measuring a home’s square footage. Each state has its own rules, although most follow recommendations for the American National Standards Institute (ANSI).
A professional appraiser will likely measure your square footage from the exterior walls, which is what the ANSI recommends.
How to calculate the square footage of a room
Step 1: Sketch out the floor plan of your home
It doesn’t have to be the most accurate picture, but sketching out the floor plan helps you keep things in order as you measure square footage.
As you take your measurements, add each number to your sketch to make sure nothing is missed.
Pro tip: Use graph paper to make sketching the floor plan easier by using a built-in grid.
Step 2: Gather your measuring tools
Before you begin measuring, it’s crucial to have the right tools available. The tools you’ll need include:
- Tape or laser measure
- Graph paper
- Pencil
- Calculator
Step 3: Measure each room
Start by measuring your interior walls from corner to corner. Then record them on your sketch.
Don’t forget about closets, pantries, and other small rooms that typically count toward your square footage.
Step 4: Calculate areas by shape
After you measure the walls in your home, it’s time for some basic math. Use the formula for calculating the area of your room’s shape to find the square footage.
Be sure to measure the room in feet to simplify your calculations by rounding up to the nearest foot.
You can use an app or a geometric calculator to make the process easier. And we have a cheat sheet for you below to calculate the area of these room shapes:
Step 5: Find your total living area
Once you calculate the area of every room (and record it on your sketch), it’s time to determine your total square footage.
To do this, simply add up the area of all your rooms to get the total area for your house.
This will give you a good idea of the total square footage of your home — as long as the calculations for each room were accurate.
How to calculate the square footage of a rectangular room
Chances are that most, if not all, of the rooms in your house are rectangular. Which is good news because the area of a rectangle is easy to calculate.
To find the area of a rectangle, multiply length by width. Or, to put it another way, multiply the length of the longest wall by the length of the shortest wall.
This is how the formula looks written out:
A = L x W
Where A equals area in square feet, L equals length in feet, and W equals width in feet. Take the following room as an example:
First, measure the length of the longest wall, which is 20 feet, by the length of the shortest wall, which is 15 feet.
Then multiply 20 by 15 and get 300, making the area for this room 300 square feet.
What about alcoves and oddly shaped rooms?
Don’t worry if your room isn’t rectangular. Simply measure the area of the alcove using the same equation as above (assuming it’s a square or rectangle). Then, add the total to the area of the main room.
If you have an oddly shaped room, such as an L-shape, consider splitting it into square or rectangular sections and treating them as two separate areas.
Not every space is linear, but you can still determine the square footage of an area by dividing it into shapes and calculating the area of each shape individually.
How to calculate the square footage of a triangular room
Triangular rooms aren’t the most common, but some homes do have them. For example, you may have a triangular corner of a room that has been converted into a closet or pantry.
Fortunately, finding the area of a triangle is easy. Multiply the length of one side by the height of the triangle, and then divide the answer by two. Here’s how:
The first step is to measure one side of the triangle. This side will be your base. In the above image, the base is four feet.
Then, imagine a perpendicular line traveling from the base to the opposite corner of the triangle. In the picture above, the dotted line represents your base height. In this example, the base height is 3.5 feet.
Then multiply the base by the base height, which gives us 14.
Finally, divide the answer by two. For the tiny room above, the final answer is 7 square feet.
Calculating the area of a right triangle
Calculating the area of a right triangle — a triangle where one corner is 90 degrees — is even easier. Simply multiply the two sides that are joined together at the 90-degree corner and then divide the answer by two.
How to calculate the square footage of a circular room
Calculating the square footage of a circular room is a bit more complicated.
If your room is a perfect circle, you can calculate the area by multiplying pi (which is approximately 3.14) by the radius of the room squared.
Here’s an example of how to calculate the area of a circle:
The first step is to determine the radius of the room. To do that, simply measure from the center of the room to the wall. If you can’t find the center, measure the diameter of the room (i.e., the furthest distance between the walls) and divide it by two.
In the example above, the radius is five meters. So you square the five, which simply means multiplying five by itself, and get 25.
Then multiply 25 by 3.14 (the rounded figure for pi).
The answer is 78.5. Since you round to the nearest whole foot when calculating the area of a house, the area of the room is 79 square feet.
How to calculate the square feet of a house
Calculating the entire square footage of your house is simple once you break it down into pieces. Measure each room individually, and then total them up to find your GLA.
Here’s how you would find the total square footage of a 3-bedroom, 2-bathroom house:
| Room | Dimensions (ft) | Square Footage |
|---|---|---|
| Living Room | 18 x 16 | 288 sq ft |
| Kitchen & Dining | 14 x 14 | 196 sq ft |
| Primary Bedroom | 14 x 13 | 182 sq ft |
| Primary Bathroom | 8 x 10 | 80 sq ft |
| Bedroom 2 | 11 x 11 | 121 sq ft |
| Bedroom 3 | 11 x 11 | 121 sq ft |
| Hall Bathroom | 5 x 8 | 40 sq ft |
| Laundry Room | 6 x 8 | 48 sq ft |
| Hallways/Closets/etc | Irregular Shapes | 464 sq ft |
| Gross Livable Area | Sum of all Room Dimensions | 1,540 sq ft |
What if you have multiple floors?
If you own a multi-level home, you must measure the interior of each room on every floor.
You can’t simply double the square footage of the main floor because your rooms could have different dimensions or sections of non-livable space.
For example, if you have an unfinished garage on the first floor, none of that space would count toward your GLA.
What counts as square footage?
| ✅ Rooms included in square footage | ❌ Rooms excluded from square footage |
|---|---|
| Living and family rooms | Basements |
| Kitchens | Garages |
| Dining rooms | Attics |
| Bathrooms | Rooms with sloped ceilings |
| Bedrooms | Pool houses |
| Enclosed and heated porches | Guesthouses |
| Finished attics (ceilings higher than 7 feet) | Storage buildings |
| Finished basements (above grade) | Mother-in-law suites |
To better understand what you can include in your home’s gross livable area, you can follow the ANSI Z765 guidelines used by most appraisers:
- Finished, heated, and livable spaces
- Rooms at ground level and above (no basements)
- Ceilings need to be 7 feet or higher
- No storage, mechanical rooms, or garages
The ANSI standard also measures from the exterior of the home, including the thickness of the wall.
This means that an appraiser will likely have a larger square footage for your home than you would if you measured the interior walls. However, measuring the interior space can be more helpful for estimating repair projects, such as new flooring.
Finished vs. unfinished vs. livable space
You typically hear a few different terms when defining square footage, such as finished, unfinished, and livable space. Each type of space can impact your home’s GLA and which rooms you should count toward GLA when measuring.
Finished space is a fully completed area. These spaces include:
- Completed walls with drywall or paneling with paint or wallpaper
- Finished flooring with carpet, hardwood, or tile
- Baseboards, trim, and lighting fixtures
- Meets codes for insulation and habitability requirements
Unfinished spaces aren’t fully completed areas. These often have:
- Bare concrete floors, exposed studs, or rafters
- Unfinished ceilings with exposed wiring or plumbing
Examples include unfinished basements, attics, or garages
Livable space is a finished area intended for daily living. These spaces feature:
- All of the qualities of finished spaces
- Permanent heating and 7+ foot ceilings
Livable space is also typically above grade, and it’s where you measure square footage. However, you may consider a finished basement as a livable space, even though it doesn’t count toward the GLA.
State differences concerning gross livable area (GLA)
While ANSI Z765 guidelines are the typical standard (and required for Fannie Mae loans), some states have different rules about GLA.
- Colorado, Minnesota, and other states include finished basements in total square footage listings but often describe them as “below-grade finished”
- In California, finished basements and garages may or may not be included in square footage, AND non-permitted finished spaces may be included with a disclosure
- Many New England states with historic homes will include finished attic spaces, even if they don’t meet the 7+ foot ceiling rule
- Texas and Florida allow converted garages to be included in GLA as long as they are finished, climate-controlled, and match the home
To get the best picture of what is and isn’t included in your area, you should consult a trusted real estate agent or appraiser.
Why is square footage important?
The square footage of your home has a significant impact on how you calculate for repairs, how taxes are appraised, and your listing price when you go to sell. Here’s why:
How square footage impacts property taxes
The size of your house has a direct impact on your property taxes. Tax assessors use your home’s square footage to determine how valuable your home is and calculate its tax rate.
Homes with more GLA will have higher taxes by default, and some property taxes are calculated based on finished space, not just GLA.
Why is square footage necessary for repairs or expansions
Whether you’re remodeling on your own or hiring a contractor, knowing your home’s square footage is essential.
Many materials, such as flooring, are priced by the square foot, and remodeling professionals may also calculate estimates based on square footage. If you don’t understand your home's size, you may miscalculate your repair budget.
Some zoning laws include square footage restrictions and limit how much you can add on to your house. Building too big could prevent your renovation from receiving the necessary permits.
Square footage and listing prices
The size of your home is a significant factor in determining its listing price.
Larger homes may sell for more in some neighborhoods, while in others, additions and finished basements price you out of your area.
It’s essential to consult a trusted real estate agent to understand the actual value of your home’s square footage. They can perform a comparative market analysis (CMA) and set a realistic listing price based on comparable homes in the area.
How to calculate the square footage of a house for appraisal
Some multiple listing services (MLSs) don’t require professional measurements for listings, allowing agents and sellers to report square footage based on homeowner measurements or tax records.
However, a professional appraisal that adheres to ANSI standards is necessary in some cases. Since 2022, Fannie Mae[1] mortgages have required appraisals that follow these guidelines for all potential lenders.
Opting for a professional appraisal of your home’s square footage can streamline the process for anyone who wants to buy through Fannie Mae mortgage programs.
Additionally, a professional assessment can make it easier to list your home if your local MLS requires an official measurement.
Pro tip: You can often check your local property assessor’s record for existing GLA values on your home. If they are current, these records may be a substitute for the appraisal process.
How can a real estate agent help?
Consulting a real estate agent is a great way to ensure you’re prepping your home for sale in the right way. Working with a realtor can help you:
- Estimate an accurate listing price based on square footage
- Keep you from over- or underreporting gross livable area
- Invest in the right renovations that impact square footage value
To work with the best agent in your area, try Clever.
Clever can match you with trusted agents in your area from popular brokerages like Re/MAX and Compass to help prepare your home for sale, all at a low 1.5% commission rate.
FAQs
Most spaces in the home are included in its square footage, including stairways, hallways, and closets.
Finished attics will be included if they have a ceiling height of 7 feet or more. Covered and enclosed porches can also be included if they are climate-controlled.
Most appraisers measure the exterior of the home to determine gross living area (GLA) according to ANSI guidelines. This includes all closets, hallways, stairwells, and the thickness of the walls.
Yes, all closets and hallways above grade count toward the square footage of your home. If you are measuring on your own, be sure to include those measurements.
No. Garages are not considered a part of a house’s gross living area, but you can still mention in your listing that your house includes a garage.
No. Your basement (even a finished one) cannot be included as part of the gross livable area in most states.
The average cost is between $300 and $400, but this depends on your location, the size of your house, and other factors. The range is from $250 to nearly $500.