Square Footage Calculator

Find the square footage of an area by selecting a shape and entering the dimensions. Include the price per sq ft to estimate the total cost.

Select a Shape:

Rectangle Square Footage

Optionally enter the price per square foot
$

Square Square Footage

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$

Border Square Footage

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$

Trapezoid Square Footage

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$

Parallelogram Square Footage

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$

Rhombus Square Footage

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$

Triangle Square Footage

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$

Circle Square Footage

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$

Ellipse Square Footage

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$

Sector Square Footage

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$

Segment Square Footage

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$

Pentagon Square Footage

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$

Hexagon Square Footage

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$

Octagon Square Footage

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$

Regular Polygon Square Footage

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$

Area in Square Feet:

 

Total Price

$
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How to Calculate Square Footage

Square footage is just an area measured in feet, and it’s often abbreviated sq ft or ft2. One square foot is equal to a square area with a length and width of 12 inches.

The measurement is commonly used for construction, home remodeling, and renovation projects such as carpeting, hardwood flooring, tiling, drywalling, painting, and gardening material estimates.

You can calculate the square feet of a space using the area formula, which states that the area is equal to the length times the width. This is the formula for a rectangle, but we’ll cover the area formulas for different shapes below.

Square feet formula showing the area of a space is equal to the length times width

Before you multiply the length and width together, make sure each measurement is in feet.

To calculate the square footage using measurements in inches or another measurement, first convert the length and width measurements to feet, then multiply them together.

Steps to Calculate Square Feet

Find the area of a room or space in square feet by following these easy steps:

  • Measure the length and width of the area.
  • Convert these measurements to feet if they aren’t already. Convert inches, yards, or meters to feet using a converter if needed.
  • Multiply the length in feet times the width in feet (length × width). Use one of the formulas below to calculate square footage for various shapes.
  • 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.

For example, let’s find the square feet of a room that is 12′ wide by 16′ long.

area = 12′ × 16′
area = 192 sq ft

Square Footage Formulas

Use the formulas below to find the square footage for various shapes. Convert all measurements to feet before using the formulas.


Rectangle

sq ft = l × w

l = length
w = width

Diagram of a rectangle showing l = length and w = width

Rectangular Border

sq ft = (l – (2 × b)) × (w – (2 × b))

l = outer length
w = outer width
b = border width

Diagram of a border showing l = outer length, w = outer width, and b = border width

Circle

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.

Diagram of a circle showing r = radius

Triangle

s = 1/2(a + b + c)
sq ft = s(s – a)(s – b)(s – c)

a = edge a
b = edge b
c = edge c

Diagram of a triangle showing a = edge a, b = edge b, and c = edge c

Our area calculator has even more formulas for different shapes.

How to Convert to Square Feet

You can also calculate square feet by converting a known area that’s in different units of measure. You can convert square inches, square yards, or metric units such as square meters to square feet using one of the formulas below.

Square Inches:
sq ft = sq in ÷ 144

Square Yards:
sq ft = sq yds × 9

Square Meters:
sq ft = sq m × 10.764

You can use an area converter to convert any area measurement to sq ft.

How to Calculate the Square Feet of a Home or Residence

As noted above, measuring the square footage of a house is important in real estate and for common improvements. Unlike measurements for a flooring project, when you’re measuring the area of a home or residence for real estate purposes, some special considerations apply to determine the inhabitable square footage.

Since the livable size of a home determines the market value, appraisal price, and property taxes, getting an accurate measurement is important.

Only livable rooms 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 like bedrooms and closets count toward the square footage of a home, while outdoor spaces such as the garage typically do not. In fact, the American National Standards Institute has defined rules[1] for what counts as finished area and which rooms contribute to the gross living area (GLA) of a home.[2]

To calculate the total area of a home, measure each room in feet using a tape measure. Then, for each room, multiply the length of the room by the width to get the square footage.

For oddly shaped rooms, split the room into smaller, easily measurable sections, and calculate the area of each section.

graphic showing how to measure the square footage of an oddly shaped room or complex area

Finally, add the area measurements together to find the total square foot value. The calculator above can help find the square feet of one room or multiple rooms using this method.

We also have great resources on how to measure rooms and complex spaces.

How to Calculate Price per Sq Ft

To calculate the price per square foot of your home, divide the total price by the number of square feet.

price per ft2 = total price ÷ total ft2

For example, to find the price per ft2 of a home that costs $200,000 and is 2,000 ft2, use this formula.

price per ft2 = $200,000 ÷ 2,000 ft2
price per ft2 = $100

If you’d prefer not to do the math, you can also use our unit price calculator to calculate the price per square foot.

References

  1. American National Standards Institute, Square Footage — Method for Calculating, ANSI, Z765-2021, approved March 2021,
  2. Fannie Mae, Standardized Property Measuring Guidelines, December 2021, https://singlefamily.fanniemae.com/media/30266/display