Free Square Footage Calculator
Quickly calculate square footage for rooms, yards, flooring projects, and more. Enter your measurements and get an instant result — no sign-up required. Supports rectangles, circles, triangles, and trapezoids so you can measure any shape of space.
How to Calculate Square Footage
Rectangle or Square
Multiply the length by the width: Area = Length x Width. This is the most common formula, used for standard rooms, yards, and lots.
Circle
Use the formula Area = pi x radius x radius (pi is approximately 3.14159). Measure from the center to the edge to get the radius.
Triangle
Multiply the base by the height then divide by two: Area = 0.5 x Base x Height. Useful for triangular rooms, gable ends, and angled sections.
Trapezoid
Add the two parallel sides, multiply by the height, then divide by two: Area = 0.5 x (Side A + Side B) x Height. Common for irregularly shaped lots and rooms.
Common Square Footage Calculations
| Dimensions | Square Feet |
|---|---|
| 10 x 10 ft | 100 |
| 10 x 12 ft | 120 |
| 12 x 12 ft | 144 |
| 12 x 15 ft | 180 |
| 15 x 15 ft | 225 |
| 15 x 20 ft | 300 |
| 20 x 20 ft | 400 |
Square Footage Conversion Chart
| Square Feet | Sq Meters | Sq Yards | Acres |
|---|---|---|---|
| 100 | 9.29 | 11.11 | 0.0023 |
| 500 | 46.45 | 55.56 | 0.0115 |
| 1,000 | 92.90 | 111.11 | 0.0230 |
| 2,000 | 185.81 | 222.22 | 0.0459 |
| 5,000 | 464.52 | 555.56 | 0.1148 |
What is a Square Foot?
A square foot is a unit of area measurement equal to a square that is one foot on each side. It is part of the imperial system of measurement used primarily in the United States, Canada, and the United Kingdom. One square foot equals 144 square inches, or approximately 0.0929 square meters.
The square foot has its roots in the ancient practice of measuring land and buildings using the human foot as a standard unit. Over centuries, measurements were standardized, and the square foot became a reliable unit for area in countries using the imperial system. While much of the world has adopted the metric system and uses square meters, the square foot remains the dominant area unit in American real estate, construction, and home improvement.
In everyday life, square footage comes up most often when buying or renting a home. Real estate listings almost always include the total square footage of a property, which gives buyers and renters a quick sense of how large the space is. A studio apartment might be 400 to 600 square feet, while a typical single-family home in the United States runs between 1,500 and 2,500 square feet.
Square footage is also essential for construction and renovation projects. Contractors use it to estimate how much flooring, paint, drywall, insulation, or roofing material a project requires. Getting an accurate square footage measurement before purchasing materials can save significant time and money by reducing waste and avoiding extra trips to the hardware store.
For landscaping and outdoor projects, square footage helps you figure out how much sod, mulch, gravel, or pavers you need. Even for simple tasks like seeding a lawn or laying a patio, knowing the area in square feet lets you calculate the right amount of materials from product coverage rates listed on packaging.
Frequently Asked Questions
How do I calculate the square footage of a room?
Measure the length and width of the room in feet, then multiply them together. For example, a room that is 12 feet long and 10 feet wide has 120 square feet. For irregular rooms, divide them into rectangles, calculate each area separately, and add the results.
How many square feet is a 12x12 room?
A 12x12 room is 144 square feet. You get this by multiplying 12 feet by 12 feet. This is a common bedroom size and is often used as a reference point when comparing room sizes.
What is the formula for square footage of a circle?
The formula for the area of a circle is pi times the radius squared (pi x r x r). Pi is approximately 3.14159. So a circular room with a radius of 10 feet would be about 314.16 square feet.
How do I convert square feet to square meters?
To convert square feet to square meters, multiply the square footage by 0.0929. For example, 1000 square feet equals approximately 92.9 square meters. To go the other direction, multiply square meters by 10.764 to get square feet.
How many square feet are in an acre?
There are 43,560 square feet in one acre. An acre is a unit of land area commonly used in the United States and United Kingdom. A standard American football field is about 1.32 acres, or roughly 57,600 square feet including the end zones.
What is the square footage of an average house?
The average new single-family home in the United States is approximately 2,300 square feet, according to U.S. Census data. However, home sizes vary widely by region, age of construction, and housing type. Condos and townhomes tend to be smaller, often ranging from 800 to 1,500 square feet.
Can I calculate square footage in inches?
Yes. Measure the dimensions in inches, multiply to get square inches, then divide by 144 to convert to square feet (since 1 square foot equals 144 square inches). Our calculator lets you enter measurements in feet, but you can convert inches to feet first by dividing by 12.
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