Square Footage Calculator
Select a shape to start finding the square footage of any area. Include the price per foot to determine the cost of materials. Enter values in inches, feet, yards, centimeters, or meters.
Rectangle Square Footage
Square Square Footage
Border Square Footage
Trapezoid Square Footage
Parallelogram Square Footage
Triangle Square Footage
Circle Square Footage
Ellipse Square Footage
Sector Square Footage
Regular Polygon Square Footage
How to Find Square Footage
Square footage is just an area, measured in feet, and it’s often abbreviated sq. ft. or ft2. It’s often used for construction, home remodeling, and renovation projects such as carpeting, hardwood flooring, tiling, framing, drywalling, painting, and gardening material estimates.
Find square feet just like you would find the area of a shape, by multiplying the length times the width.
Before multiplying the length and width together, convert all measurements to feet. To calculate the square footage when measurements are in inches or another unit of measure, first convert the length and width measurements to feet, then multiply.
- Measure the length and width of the area.
- Convert these measurements to feet if they aren’t already. Convert inches to feet, convert yards to feet, or convert meters to feet.
- Multiply the length in feet times the width in feet
- To estimate the cost of materials, multiply the total square footage by the price per square foot.
- If the area is not a simple shape, break it into manageable parts and calculate the area of each part separately and then add them together. For example, to measure a floor of your home, calculate the square feet of each room, then add all area measurements together to derive the total square footage.
How to Calculate Square Footage for Different Shapes
Use the formulas below to find the square footage for various shapes. Convert all measurements to feet before using the formulas.
sq. ft. = (l – (2 × b)) × (w – (2 × b))
l = outer length
w = outer width
b = border width
sq. ft. = πr2
r = radius
π = 3.14159265359
If you know the diameter of the circle you can find the radius by dividing the diameter in half.
Calculate square feet of a circle
s = 1/2(a + b + c)
sq. ft. = s(s – a)(s – b)(s – c))
a = edge a
b = edge b
c = edge c
Our area calculator has even more formulas.
Calculating the Square Feet of a Home or Residence
If you’re measuring the square footage of a home or residence, there are some special considerations that apply to determine inhabitable square footage. The livable size of a home helps determine the market value and price of a home and also helps buyers understand the size of the home.
Only rooms that are livable, with finished walls, floor, and ceiling, count toward the finished area of the home. For a room to be considered livable the space should be finished and should have heating or air conditioning as applicable. Indoor spaces count toward the square footage of a home, outdoor spaces typically do not.
To calculate the total area, measure each room in feet using a tape measure, then multiply the length and width of each room to get the square footage, then add them all together. The calculator above can help determine the square feet of each room, then simply add all of the room’s areas together. Learn more about how to measure a room.
To calculate the price per square foot of your home, divide the total price by the number of square feet. For example, a home that costs $200,000 and is 2,000 ft2 is 200,000 ÷ 2,000, or $100 per ft2.