Calculating Square Footage: Which of These ‘Gray’ Areas Should You Count? (2024)

It’s critical to calculate your home’s gross living area to determine your home’s value. Square footage isn’t always so cut-and-dried, though.

For instance, you may need help calculating those hard-to-measure spaces like staircases or awkward areas like a circular turret. And spaces like your screened-in porch, finished basem*nt, or renovated attic fall into gray areas that may or may not officially count as living space.

Underestimate your square footage — and you might accidentally agree to sell your home for less than it’s worth. Overestimate your home’s size, and your appraisal may come in low and threaten the sale.

We spoke with a seasoned appraiser and a top real estate agent to help you accurately calculate your home’s square footage. Let’s take a closer look at how to measure those awkward spaces and gray areas.

How do I find my home’s square footage?

“There are a lot of different ways to find the square footage of a home. Sometimes the information is pulled from the county tax assessor or pulled directly from an architectural floor plan,” explains top-selling Chicago-based real estate agent Scott Curcio.

1. Start by reviewing paperwork from when you purchased the home

The listing documents, sales contract, and home appraisal report will include the total square footage.

Just note that the square footage calculation from your home sale may not be 100% accurate. Regulations dictating what qualifies as livable space may have changed over the years. Plus, that calculation won’t account for any extra square space you’ve added through remodeling projects or room additions.

2. Reach out to a real estate agent for an updated estimate

Reaching out to an experienced local real estate agent in your area to find out which spaces in your house can be included in the total square footage is the best way to get accurate guidance on what qualifies as countable living space in your house.

What’s included in a home’s square footage?

Main living spaces make up the bulk of your home’s square footage, including the kitchen, the living room, the dining room, bedrooms, and bathrooms. Stairways and hallways are also included, although these spaces are not as easy to measure as square rooms.

Other areas, like finished basem*nts and attics, or enclosed porches, may or may not count as living space (and therefore, square footage). It all depends on your local regulations and practices. We’ll dive into details on this later.

“In the city of Chicago, we see a difference in the way square footage is calculated in the city versus the suburbs,” Curcio shares. “For example, in the city, we generally count basem*nt square footage as part of the overall square footage of a home. However, in certain suburban areas, they will not count it because they’re below grade.”

How much value does adding square footage yield?

Home value per square foot varies from state to state, city to city, and even neighborhood to neighborhood. For example, in the Western regions, like California, square footage runs around $190 per square foot, whereas in the Midwest, like Wisconsin, you’ll only get an additional $110 per square foot. That’s a difference of $19,000 versus $11,000 for the addition of a 10-foot by 10-foot room onto your home.

Increasing your home’s value by $10,000 to $20,000 sounds great, but don’t forget to factor in the cost to add extra square footage. Let’s say you add a 200 square foot room to your ground floor. That addition will potentially add $20,000 to $40,000 to your home’s value, but if it costs you between $16,000 to $40,000, you’ll just break even at the end of the day.

How is square footage measured?

To calculate square feet you multiple the room’s length by its width. For example, a space that measures 10 feet by 10 feet totals out to 100 square feet.

Length x Width = Area
Ex. 10 ft. x 10 ft. = 100 square feet

While this may sound simple enough, it can be complicated measuring the square footage of a house due to odd-shaped spaces and living space gray areas.

“Here in North Carolina, square footage is calculated to the outer edge of the dwelling. So to properly calculate the square footage, an owner would need to calculate the area by multiplying the length by width, and including the wall thicknesses in their measurements,” explains Matt Harmon a North Carolina-based, state-certified property appraiser.

“For example, if a square house measured 20-foot by 20-foot when measuring to the interior walls, and the walls were 0.4-foot thick, then to calculate the area, you’d need to multiply 20.8 by 20.8 to find the exact square footage.”

However, if you’re selling a condo in a multi-family unit — meaning that you only own the interior space, not the exterior building — you would only measure square footage from interior wall to interior wall.

Finished basem*nts and attics do not add to the primary square footage

The square footage of a finished basem*nt that is below grade (underground) adds less value than the square footage of above grade living space.

So if your home is 2,000 square feet, and you have an additional 1,000 square-foot finished basem*nt, you cannot claim to have a 3,000 square-foot home if your local area values basem*nt spaces at a lower dollar amount than the rest of the house.

In this instance, you would list your home at 2,000 square feet and then include the additional 1,000 square feet of living space in your finished basem*nt in the listing notes.

The same is true of finished attic spaces. If the space has sloping roofs, inadequate windows, and forms of egress, then the area may not count towards your overall square footage.

To determine if your space makes the cut, consult an appraiser or an experienced real estate agent.

Here’s the deal with square footage gray areas

These are the top 10 gray areas that may or may not be counted in your home’s square footage total.

1. Basem*nts

Unfinished: If your basem*nt is unfinished (with exposed studs, cement, unpainted or plastered drywall, etc.), then it does not count towards your home’s square footage. You may, however, include the size of the basem*nt in your listing description.

Finished: Finished basem*nts may count towards your home’s overall square footage, depending on the real estate regulations in your area. For example, a finished basem*nt bedroom can count as additional living space and as a bedroom (if it has adequate forms of egress).

That below-grade bedroom may not be as valuable as your above-grade bedrooms, though. While you can include its area in the total square footage of living space, an appraiser will likely measure finished basem*nt spaces separately because below grade is valued less by the bank.

For example, a 10-foot by 10-foot bedroom upstairs may be valued at $130 per square foot, which equals $13,000. However, a 10-foot by10-foot bedroom in the basem*nt may only be valued at $90 per square foot, which equals out to $9,000 for that space.

2. Garages

“Regular garages for parking cars are never included in the living area,” advises Harmon. “However, if they have finished walls, floors, ceilings — and are adequately heated by a permanently installed heat source — then they would meet the criteria for living area. Typically, when this is done, the sliding garage door is either removed or covered by a finished sheetrock wall.”

3. Closets

Closets are always included in your home’s square footage, as long as its construction meets your state’s square footage guidelines.

4. Bathrooms

Bathrooms are also always included in your home’s square footage if they meet the minimum requirements. For example, a half-bathroom in your free-standing garage cannot be counted because it is not attached to the main house.

In some states, a finished basem*nt bathroom may not count if it’s in an unfinished basem*nt that separates it from the rest of the house.

5. Stairs

Stairs that are finished and connected to the living area count towards your home’s square footage.

“In North Carolina, stairs are included in the floor they descend from as well as the floor they descend to, not to exceed the opening in the floor on the upper level,” Harmon adds.

Instructions on measuring your stairs for carpet can help you determine your stairs’ square footage.

6. Covered porches and sunrooms

Open-air, covered porches never add to your home’s square footage, even if they are elevated to the same level as the rest of the house by the foundation. Screened-in porches do not qualify as living space either.

Four-season sunrooms count towards the total square footage. These sunrooms should have a built-in heat source and point of connection to the main living area.

7. Guesthouses and accessory dwelling units

Guesthouses or accessory dwelling units (ADUs) that are completely detached from the primary residence cannot be counted within the overall total of the main home’s square footage.

Guesthouses that are attached to the primary residence in a way that makes them accessible from the main home can be counted in the overall square footage, even if the guest home has its own entrance.

8. Patios

Like open-air porches, patios are not indoor living spaces, so you can’t include them in your home’s square footage.

9. Attics

Unfinished: An unfinished attic does not add to the total square footage.

Finished: Whether or not your finished attic adds square footage depends on the room’s design and your area’s customs.

“In our market area, finished attics that meet the criteria for a living area are included and counted as normal second or third-floor square footage,” advises Harmon.

Most rooms must legally have a ceiling height of at least seven feet to count as living space. Attics often have sloped ceilings thanks to the roof, so only a portion of the room can be counted towards your square footage.

According to the North Carolina Real Estate Commission’s Residential Square Footage Guidelines, “you may also include a living area the portion of the room with a ceiling height of at least five feet if at least one-half of the finished area of the room has a ceiling height of at least seven feet.”

In other states, you cannot count an attic toward your square footage if the ceiling height falls below seven feet. That’s why it’s best to consult a local real estate agent or appraiser who knows your area’s guidelines to determine if your space adds to the square footage.

10. Balconies

Open-air balconies are never included in your home’s overall square footage.

Do your research before measuring your square footage or adding more space

Overestimating your home’s square footage can hurt you financially when the time comes to sell, so it’s always best to check with an expert before calculating your home’s square footage. The same advice holds true if you’re thinking of expanding your house.

Before you embark on a project to add livable square footage to your property, research zoning laws to determine the maximum square footage you’re allowed to have on your property. Otherwise, you could spend money on adding square footage that won’t increase your property value.

“Property lots often have maximum allowable square footage that’s allowed to be finished as living space. However, it’s not uncommon that a homeowner will finish out an attic space or a basem*nt beyond the maximum allowable square footage,” Curcio notes.

When in doubt, reach out to a local real estate agent for help. They can advise on if you can (and should) add square feet to your property.

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