About the Square Footage Calculator

Square footage is the most common measurement in real estate, construction, interior design, and home improvement. Whether you are buying a home, installing flooring, estimating paint, calculating property taxes, or comparing apartment sizes, knowing the exact square footage is essential.

Our square footage calculator handles the most common shapes found in homes and properties: rectangles, squares, triangles, circles, and trapezoids. Simply enter your measurements, and the calculator provides the area instantly along with conversion to square yards and square meters.

Why Square Footage Matters

Real Estate Transactions

The listed square footage of a home directly impacts its market value. In most markets, price per square foot is the standard metric buyers use to compare properties. A miscalculation of even 100 square feet can affect a home's perceived value by thousands of dollars.

Flooring and Renovation Costs

Flooring, paint, tile, and carpet are all priced by the square foot. Accurate measurements prevent ordering too much material or running short mid-project.

Property Taxes

Many jurisdictions base property tax assessments on the total heated square footage of a home.

HVAC Sizing

Heating and cooling systems are sized based on the square footage of the space they serve. An undersized system runs constantly; an oversized system cycles too frequently, reducing efficiency.

How to Calculate Square Footage

Rectangular or Square Rooms

Formula: Area = Length × Width

Example: A living room measures 18 feet long and 14 feet wide. Area = 18 × 14 = 252 square feet

Triangular Areas

Formula: Area = (Base × Height) ÷ 2

Example: A triangular gable end measures 30 feet wide at the base and 12 feet tall. Area = (30 × 12) ÷ 2 = 180 square feet

Circular Areas

Formula: Area = π × Radius²

Example: A round dining nook has a radius of 8 feet. Area = 3.14159 × 8² = 3.14159 × 64 = 201 square feet

Trapezoidal Areas

Formula: Area = (Base₁ + Base₂) ÷ 2 × Height

Example: A bay window wall measures 12 feet at the bottom, 8 feet at the top, and extends 3 feet into the room. Area = (12 + 8) ÷ 2 × 3 = 10 × 3 = 30 square feet

Measuring an Entire House or Apartment

To calculate the total square footage of a home:

Measure each room individually using the formulas above
Add all room areas together
Include hallways, closets, and staircases
Decide whether to include basements, attics, and garages

What Counts as Living Space?

Space	Typically Included?	Notes
Bedrooms	Yes	Standard living space
Bathrooms	Yes	Standard living space
Kitchen	Yes	Standard living space
Living/family rooms	Yes	Standard living space
Hallways	Yes	If inside heated envelope
Closets	Yes	If inside measured rooms
Stairs	Yes	Count once at footprint
Finished basement	Sometimes	Must meet ceiling height code
Finished attic	Sometimes	Must meet ceiling height code
Garage	No	Not living space
Unfinished basement	No	Not living space
Porch/deck	No	Outdoor space

ANSI Standard: For real estate listings in the US, the American National Standards Institute (ANSI) requires ceiling heights of at least 7 feet for main spaces and 5 feet under sloped ceilings to count as living area.

Converting Square Footage

From	To	Multiply By
Square feet	Square yards	÷ 9
Square feet	Square meters	× 0.0929
Square yards	Square feet	× 9
Square meters	Square feet	× 10.764
Acres	Square feet	× 43,560
Square feet	Acres	÷ 43,560

Example conversions:

500 sq ft = 55.6 sq yards
1,200 sq ft = 111.5 sq meters
10,000 sq ft = 0.23 acres

Average Square Footage by Room

Room	Typical Size	Average Sq Ft
Master bedroom	14' × 16'	224 sq ft
Standard bedroom	11' × 12'	132 sq ft
Living room	16' × 20'	320 sq ft
Kitchen	12' × 14'	168 sq ft
Dining room	12' × 12'	144 sq ft
Master bathroom	10' × 12'	120 sq ft
Half bathroom	5' × 7'	35 sq ft
Two-car garage	20' × 24'	480 sq ft

Average Home Sizes by Type

Home Type	Average Square Footage	Notes
Studio apartment	400-600 sq ft	Single open space
1-bedroom apartment	600-800 sq ft	Separate bedroom
2-bedroom apartment	900-1,200 sq ft	Family-sized rental
Small house (2BR)	1,000-1,500 sq ft	Starter home
Medium house (3BR)	1,600-2,300 sq ft	Average US home size
Large house (4BR+)	2,400-3,500 sq ft	Family home
McMansion	4,000-6,000+ sq ft	Luxury custom home

Cost Per Square Foot by Project

Project	Cost per Sq Ft	Example (500 sq ft)
Interior painting (DIY)	$1-3	$500-1,500
Interior painting (pro)	$3-7	$1,500-3,500
Hardwood flooring	$8-15	$4,000-7,500
Carpet installation	$3-8	$1,500-4,000
Tile flooring	$8-20	$4,000-10,000
Laminate flooring	$4-10	$2,000-5,000
New construction	$150-300	$75,000-150,000
Home addition	$200-400	$100,000-200,000

Measuring Tips for Accuracy

Measure in feet and inches: Record measurements as 12'6" rather than rounding to 13 feet
Measure at the widest points: For irregular rooms, measure the maximum length and width
Use a laser measure: More accurate than a tape measure for long distances
Measure twice: Double-check all measurements before calculating
Break complex rooms into shapes: An L-shaped room is two rectangles
Subtract large obstructions: Fireplaces and built-ins can be subtracted for flooring
Add 5-10% for waste: When ordering materials, round up to account for cuts and errors

Frequently Asked Questions

How do I measure square footage for an L-shaped room?

Divide the room into two rectangles, calculate each area separately, and add them together.

Does ceiling height affect square footage?

No. Square footage measures floor area only. Cubic footage (volume) accounts for ceiling height.

How do appraisers measure square footage?

Licensed appraisers typically measure the exterior footprint and subtract non-living areas like garages. Interior measurements are used for complex layouts.

Why does my measured square footage differ from the county records?

County records may include unfinished spaces, use exterior measurements, or contain errors. Finished basements and additions may not be updated in public records.

What is the difference between gross and net square footage?

Gross square footage includes everything within the exterior walls. Net square footage (or usable square footage) excludes walls, stairwells, and mechanical spaces.

Square Footage Calculator