Calculate the area of any space in square feet. Supports rectangular, circular, and triangular shapes with automatic unit conversions to square meters, square yards, and acres.
Multiply by this number for multiple identical areas
Square Feet
300 ft²
Square Meters
27.87 m²
Square Yards
33.33 yd²
Acres
0.01
Your Area
300 ft²
Living Room
300 ft²
Approximate material costs for 300 sq ft
Hardwood Flooring
$1,800 - $3,600
$6 - $12 per sq ft
Laminate Flooring
$900 - $2,100
$3 - $7 per sq ft
Carpet
$600 - $1,500
$2 - $5 per sq ft
Tile Flooring
$1,500 - $4,500
$5 - $15 per sq ft
Interior Paint (walls)
$450 - $900
$1.5 - $3 per sq ft
Lawn Sod
$90 - $240
$0.3 - $0.8 per sq ft
Square footage is the area of a space measured in feet. For a rectangle, multiply length by width. For a circle, the formula is π × radius². For a triangle, multiply the base by the height and divide by two. When measuring a room, use the longest wall-to-wall dimensions and exclude built-in features like closets or alcoves if they should not count toward the total. For complex floor plans, divide the space into simple shapes, calculate each separately, and add them together.
The ANSI Z765-2021 standard (adopted by Fannie Mae) defines what counts as "finished above-grade living area" for real estate appraisals:
Home sizes have changed over the decades (source: U.S. Census Bureau, NAHB):
| Year | Median (sq ft) | Average (sq ft) |
|---|---|---|
| 1970 | 1,500 | 1,660 |
| 1990 | 1,905 | 2,080 |
| 2000 | 2,057 | 2,266 |
| 2015 | 2,467 | 2,687 |
| 2023 | 2,233 | 2,411 |
Construction and home costs vary widely by region (source: NAHB Cost of Constructing a Home):
| Region | Avg. Price/sq ft (new construction) |
|---|---|
| Midwest | $100–$140 |
| South | $110–$160 |
| West | $150–$250 |
| Northeast | $170–$280 |
| Major coastal cities | $300–$500+ |
Sources: Authority Appraisals, Redfin
Measure the length and width of the room in feet and multiply them together. A room that is 12 feet long and 10 feet wide is 120 square feet. For L-shaped rooms, split the space into rectangles, calculate each one, and add them together.
One acre equals 43,560 square feet. That's roughly the size of a football field (excluding end zones). To convert square feet to acres, divide by 43,560.
Multiply square feet by 0.0929 to get square meters. For example, 100 sq ft x 0.0929 = 9.29 sq m. This calculator performs the conversion automatically.
Use the formula A = pi x r-squared, where r is the radius (half the diameter). For a circular patio with a 10-foot diameter, the radius is 5 feet, so the area is pi x 25 = approximately 78.5 square feet.
Break the space into simple shapes (rectangles, triangles, circles). Calculate each area separately and add them together. For irregular curves, approximate with the closest simple shape or measure a bounding rectangle for an overestimate.
Under the ANSI Z765-2021 standard used by appraisers, below-grade (basement) space is not included in the above-grade living area even if it is finished. It is typically reported separately. However, finished basements still add value to a home and are noted in real estate listings.
No. Garages, whether attached or detached, are not included in a home's living area under ANSI and Fannie Mae guidelines. The space must be finished, heated/cooled, and directly accessible from the main living area to count as livable square footage.
Price per square foot is one of the most common metrics in real estate. According to NAHB data, the national average is roughly $150-200 per square foot for new construction, but this varies dramatically by region, ranging from under $100/sq ft in rural areas to $400+ in major coastal cities.
According to U.S. Census Bureau data, the median size of a new single-family home in 2023 was approximately 2,233 square feet, down from a peak of 2,467 sq ft in 2015. The average (mean) size is higher at around 2,411 sq ft due to large luxury homes pulling the number up.
Area Converter
Convert between square inches, square feet, square yards, acres, square miles, square centimeters, square meters, hectares, and square kilometers.
Paint Calculator
Calculate how much paint you need for your project. Enter room dimensions, doors, and windows to get an accurate estimate in gallons for any number of coats.