Square Footage Calculator

Find the square footage of any area, especially for construction, home remodeling, and renovation projects such as carpeting, hardwood flooring, tiling, framing, drywalling, painting, and gardening material estimates. Include the price per foot to determine the cost of materials. Enter values in inches, feet, yards, centimeters, or meters.

How to Find Square Footage

Square footage is just an area, measured in feet. Find square feet just like you would find the area of a shape, by multiplying the length times the width. Unlike a standard area measurement, all measurements need to be converted to feet before multiplying together. For finding the square footage of 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. If the area is not a simple shape, break the area into manageable parts and calculate the square feet of each part separately and then add that together. For example, to measure a floor of your home, calculate the square feet of each room, and then add all of the rooms square footage together to derive the total 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.

Square Footage Formulas for Different Shapes

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Rectangle

square footage (ft²) = length x width

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Rectangular Border

Using measurements in feet:

outside (ft²) = length x width
inside (ft²) = (length – (2 x border)) x (width – (2 x border))

border (ft²) = outside (ft²) – inside (ft²)

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Circle

square footage (ft²)= pi x (diameter / 2)²

pi = 3.14159265359

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Triangle

square footage (ft²) = (1/4) x
√(a+b+c) x (b+c-a) x (c+a-b) x (a+b-c)

See our area calculator for more area formulas.

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Measuring 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.