Total Square Footage of a House Calculator

Measure each floor or zone, subtract stair and opening voids, and compare finished living area with optional gross house square footage.

📌House presets

📐Measurements

Main floor length (ft)

Main floor width (ft)

Second floor length (ft)

Second floor width (ft)

Finished basement length (ft)

Finished basement width (ft)

Unfinished basement length (ft)

Unfinished basement width (ft)

Garage length (ft)

Garage width (ft)

Porch or covered deck length (ft)

Porch or covered deck width (ft)

Finished room count

Stair and opening deductions (sq ft)

Inclusion method

Finished square footage always starts with main, second, and finished basement, minus deductions.

Include unfinished basement in gross Include garage in gross Include covered porch in gross Count porch as finished area

📊Square footage results

Total finished

sq ft heated / finished

Gross included

sq ft by selected method

Main footprint

sq ft first-floor footprint

Average room

sq ft per finished room

🧱Area method cards

Area formula

L × W

Each rectangular zone is length multiplied by width.

Finished total

Heated

Main, upper, and finished basement areas minus openings.

Gross total

Optional

Adds selected basement, garage, and porch zones.

Conversion

10.764

One square meter equals 10.7639 square feet.

Openings

Deduct

Subtract stair wells, double-height voids, and shafts.

📋House square footage reference

Zone	Common treatment	Finished area	Gross area	Measurement note
Main floor	Always counted when finished	Yes	Yes	Measure exterior footprint or room totals consistently.
Second floor	Count finished upper living area	Yes	Yes	Subtract open-to-below spaces and stair voids.
Finished basement	Often reported separately	Yes in this calculator	Yes	Local listing rules may separate above-grade and below-grade.
Unfinished basement	Storage or mechanical space	No	Optional	Use the checkbox or basement inclusion method.
Garage	Not living area	No	Optional	Keep attached and detached garages labeled separately.
Covered porch	Outdoor covered area	No by default	Optional	Only count as finished if enclosed and conditioned.

Quick conversion	Square feet	Square meters	Use case
Small bedroom	120 sq ft	11.15 sq m	Room check
Two-car garage	440 sq ft	40.88 sq m	Gross option
Apartment size	750 sq ft	69.68 sq m	Living area
Medium floor	1,200 sq ft	111.48 sq m	Floor plate
Family home	2,400 sq ft	222.97 sq m	Total finished
Large home	4,000 sq ft	371.61 sq m	Gross review

🔢Formula breakdown

Step	Formula	Example	Why it matters
Zone area	Length × width	40 ft × 30 ft = 1,200 sq ft	Builds each floor, garage, porch, or basement area.
Total finished	Finished zones - deductions	Main + second + finished basement - openings	Shows the heated or usable living square footage.
Gross included	Finished + selected optional zones	Add garage, porch, or unfinished basement if selected	Keeps listing area and under-roof area from mixing.
Metric conversion	Sq m = sq ft / 10.7639	2,000 sq ft = 185.81 sq m	Lets plans in meters and listings in feet match.

💡Measurement tips

Use one standard: Measure all zones from the same reference, such as exterior footprint or interior room dimensions, so totals do not double count walls.

Separate below-grade space: Finished basements can be valuable, but many reports list them apart from above-grade living area.

Deduct vertical openings: Stair wells, two-story foyers, elevator shafts, and open balconies should be removed from the floor they pass through.

Label optional areas: Garage, porch, unfinished basement, and enclosed porch areas are clearest when shown separately from the finished total.

On nearly all real-estate listings, there’s one number that seems to stand out above all others: square footage. Yet it’s also the least standardized measurement of all; two homes with exact same footprint might show different sizes depending on how the seller counts their areas. Here’s what’s really being measured (and why that difference matters).

After entering your measurements into the calculator (above), it do all the hard work for you (no need to convert between inches and feet, or multiply anything yourself). There is one thing you’ll still want to determine beforehand: what “square footage” refers to, since everyone assumes it’s every inch of your home, up to the roof.

How to Measure Your Home’s Square Footage Correctly

MLS listings and appraisers is very particular, as they’re interested only in finished, heated living space. So unless your basement has permanent heat, meets code ceiling height requirements, and is wrapped in drywall, it will not count towards this figure. Even if you intend to finish the space sometime in the future, an unfinished room with concrete walls contribute nothing to your actual livable space.

First off, take measurements of your main floor, this means either going by interior measurements of each room, or taking the exterior dimensions, but be consistent. It’ll make things easier for you. Don’t mix and match; if you do, it’ll look like you inflated your numbers which raises some serious eyebrows at inspection time.

Now, if you’ve got a second story, treat it separately (it’s not easy geometry upstairs). Deduct any voids in your upper floor (i.e. Subtract any voids in your upper floor, such as an open stairwell or a two-story foyer, from your upper floor number. Why? You’re counting air as square footage, and it makes a difference when your home sits on the cusp of two different price brackets.

Another problem homeowners face: Basements, which make homes more livable, often have a separate column based off local rules and will inflate the house size artificially if counted above-grade. Although a basement can be part of your personal calculation to see what total useable square feet there is, count it separately from the figure you actualy put in the listing. The same is true for garages and covered porches, which are desirable but don’t count toward living area if they’re not fully climate-controlled and enclosed. A porch doesn’t count as living area so shouldn’t of been included when calculating the square footage of the house.

If you’re selling, clarity beats clever when it comes to presentation. Buyers are more likely to trust what they see if you show it to them clearly then if you play games with their perception. Ambiguity doesn’t help. Ambiguity doesn’t allow buyers to know what the house is worth; that’s why transparency is key. It’s very easy to break the space down into those zones where people live versus those spaces which may or may not be livable. Think of this like layers: the heated living zone (the core) and everything else (bonus inventory). See the reference table on the page for how various zones is handled in typical valuations.

If your builder is from overseas, or if your plan predates the metric system by several decades, then this also has an impact: A square foot is about 10.7 times smaller than a square meter. The number linking those two systems are what we call a coefficient, and it serves as the link between the old world and new. When you’re looking at historic versus moddern buildings, having that knowledge of their relationship is useful. Memorizing it is unnecessary; the tool will make the conversion for you, allowing you to concentrate on the actual area in question instead of the math involved.

Square feet are simply the beginning of what something is worth… They aren’t the end goal. They establish a baseline, but don’t convey character, light or flow. You might have a 2000 square foot home that doesn’t make sense layout-wise and feels smaller (and less functional) than a sixteen hundred square foot ranch with an open concept.

So compare apples to apples in your neighborhood, and rely on the numbers to guide your decisions but not your emotions regarding where you desire to livig. Measure accurately, identify your spaces clearly, and know that the space within the walls counts just as much if not more than the walls themselves.