How To Calculate Square Feet for 7 Shapes (With Examples)

How To Calculate Square Feet for 7 Shapes (With Examples)

How to calculate square feet

To calculate an area in square feet, you will need measurements for the width and length (for a square shape) or the diameter (for a circular area). It may be that the area you're looking to measure is a strange shape (such as a room or garden). In this case, dividing it up into smaller parts and doing individual calculations is a good way to calculate the overall square footage.

Let's say you have a rectangular-shaped room and you want to calculate the square footage area for flooring or carpet. The easiest method for calculating the square footage is to measure the length and width in feet and then multiply the two figures together to give you a result in ft2. If you're measuring a room for flooring, take a look at our article on how to measure for a new floor.

Should you find yourself needing to calculate an area of square feet in an 'L' shape, consider dividing the shape up into rectangular sections and treating them as separate areas for calculation (adding them together at the end). For more instructions, see our full article: how to calculate square footage.

How to Calculate the Square Feet of a Home or Residence

When measuring the square footage of a home or residence, some special considerations apply to determine the inhabitable square footage. The livable size of a home helps determine the market value and price and helps buyers understand the overall size.

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 count toward the square footage of a home, while outdoor spaces 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 of a home.[2]

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 the room’s areas together. 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.

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Convert among square inch, square foot, square yard and square meter

You could, for example, perform all of your measurements in inches or centimeters, calculate area in square inches or square centimeters then convert your final answer to the unit you need such as square feet or square meters.

To convert among square feet, yards and meters use the following conversion factors.  For other units use our calculator for area conversions.

  • Square Feet to Square Yards
    • multiply ft2 by 0.11111 to get yd2
  • Square Feet to Square Meters
    • multiply ft2 by 0.092903 to get m2
  • Square Yards to Square Feet
    • multiply yd2 by 9 to get ft2
  • Square Yards to Square Meters
    • multiply yd2 by 0.836127 to get m2
  • Square Meters to Square Feet
    • multiply m2 by 10.7639 to get ft2
  • Square Meters to Square Yards
    • multiply m2 by 1.19599 to get yd2

Length in Three Dimensions: Volume

In the case of extending your measurement by one more dimension, you add depth, height or some third direction that is mutually perpendicular to the other two. The multiplication of these three parameters gives the volume of the three-dimensional enclosed space.

The formula for a rectangular box, for example, is length times width times height, or (l × w × h). Formulas for spheres, pyramids, cones and more have shepherded many a geometry student through quizzes and exams.

How To Measure Square Footage Of A House: FAQ

There is a lot of confusion surrounding the square footage of a home, likely because of misinformation and a lack of well-known guidelines. That being said, if something seems unclear, more often than not, someone has probably wondered the same thing. Below are some commonly asked questions about how to measure the square footage of a house.

Finished Vs. Unfinished

Generally speaking, unfinished areas of the home are not to be added to its total square footage. To be included, the area must be finished. For example, you can list unfinished areas — like basements — as unfinished bonus spaces, as long as you leave them out of the overall finished square footage calculation.

Are Basements Included In House Square Footage?

Basements have become the subject of many heated debates surrounding a home’s square footage. At the very least, the answer is, well, yes and no. You see, basements — whether they are finished or not — should not be considered in a home’s total square footage, according to ANSI. That said, it is completely acceptable for homeowners to list the size of their finished basement in a separate part of the listing (separate from the home’s actual gross living area). So while today’s standards advise against adding the square footage of a finished basement to the home’s GLA, there’s no reason you can’t include the actual size of it somewhere else in the listing.

[ Want to maximize your property value? Download this step-by-step guide to making “high-ROI” home improvements. ]

Does House Square Footage Include Garage?

Whether it’s finished or not, a home’s gross living area does not include the garage. According to ANSI, “garages and unfinished areas cannot be included in the calculation of finished square footage.” Most garages can’t count towards the square footage of a home because they are not typically on the same level as the home; they are usually lower.

How Many Square Feet Are In The Average House?

The average house has about 2,400 square feet. According to the U.S. Department of Housing and Urban Development, the average square footage in 2017 was 2,426 square feet. In contrast, the average square footage was 1,660 in 1973. The number has steadily increased over the decades, reflecting Americans’ desire for more rooms and larger homes.

What Is The Square Footage Of A 12 X 12 Room?

A 12 X 12 room has 144 square feet. Simply put, square feet are calculated by multiplying the width by the length of a given room. Each room is then added up to get the total square feet of a house. Things can get complicated with add ons and other features that take away space from rooms. A good way to overcome any structural issues is to break each room into squares. Look for where walls line up and divide things in a way that makes square footage easier to calculate. You can then add up your smaller numbers to get a more accurate total.

Do Closets Count In Square Footage?

Closets do count in square footage, so long as they meet requirements applied to other areas of the house. What I mean by this is as long as closets are finished and meet the ceiling height requirements I mentioned above, they will count towards total square feet. The same logic can be applied to stairways, which are another gray area for calculating house square footage.

Total Area Vs Living Area

The total area refers to the full amount of space in a property, while the living area only includes rooms that rely on the main heating and air system. Living area is essentially another way to say square feet. On the other hand, total area will include garages, basements, balconies, and any other spaces that fall under the same roof. It is not uncommon to see both measurements given in a property listing or during an open house.

What Is Considered Livable Square Footage?

Livable square footage includes any room or space that uses the main heating and air system in a property. This includes bedrooms, bathrooms, closets, and more. The exact definition of livable square feet may be different from state to state. However, as a general rule, livable square footage refers to usable, heated spaces in a property. Keep this in mind as you calculate your house’s square feet, and ask a realtor or appraiser if you are unsure of your estimates.

How to calculate the square feet of a house

When preparing to measure the square footage of a home, be it a house, condo, or townhouse, start with a few simple supplies:

  • Paper and pencil
  • Calculator
  • Measuring tape and/or laser measuring tool

If the property is a perfect rectangle, simply measure the length and width and multiply those two numbers together. For example, if your one-story house is 60 feet wide by 40 feet long, then your property is 2,400 square feet (60 x 40 = 2,400).

However, most properties have more complex floor plans. When this is the case, it’s helpful to follow these simple steps to measure square footage.

  1. Draw a rough sketch of your entire space, labeling all of the rooms you need to measure. Include hallways and vestibules as their own “room.”
  2. Measure the length and width, in feet, of each room. Then, multiply the length by the width to calculate that room’s square footage. For example: If a bedroom is 12 feet by 20 feet, it is 240 square feet (12 x 20 = 240). For each room, write the total square footage in the corresponding space on your sketch.
  3. Once each room is measured, add up all the measurements to determine your home’s total square footage.

Note: If you live in a tract home, condo or townhome community, you may be able to get architectural drawings or master builder plans of your floor plan. These may already have your square footage calculated.

How to find the square footage of a circle

  1. Measure the diameter of your circle in feet.
  2. Divide your diameter by 2 and then square it (multiply it by itself).
  3. Multiply your total by π (3.14159265)
 The formula for calculating the area of a circle

The formula for calculating the area of a circle is: π r2 (with r being the radius of the circle, which is half the diameter). π is the symbol for pi (3.14159265).

 

Methods for how to calculate square feet for different shapes

Different shapes have different ways of calculating square footage. For all the shapes, it may be helpful to convert the measurement of the shape into square feet before making your calculation. Converting the measurements can help you keep the shape to scale, especially if the sides have different measurements, such as feet and inches or yards and meters. You could also perform the calculation and then convert the final measurement to square feet to achieve the same result.

Use the methods below to help you calculate square feet for seven different shapes:

How to calculate square feet for squares and rectangles

Squares and rectangles use the same formula to calculate square feet. This formula is:

A = length x width

In this equation, "A" is the total area of the shape in square feet. The length is the measurement of one side of the shape in feet and the width is the measurement of another side of the shape in feet. You can use the steps below to calculate the square footage of squares and rectangles with the formula above:

  1. If necessary, convert your measurements for each side of the shape into feet.

  2. Multiply the length and the width of the shape together to get the area of the square or rectangle in square feet.

How to calculate square feet for triangles

The square footage formula for triangles is:

A = 1/2 base x height

In this equation, "A" is the area of the triangle in square feet, "1/2 base" is the length of the bottom side of the triangle in feet and the height is the vertical distance from the bottom side of the triangle to the top corner in feet. You can use the following steps to calculate the area of a triangle:

  1. Convert the measurements for the base and height into feet.

  2. Divide the length of the base by two to get half of the base.

  3. Multiply half the base by the height to find the square footage area of the triangle.

How to calculate square feet for circles

To calculate the area of a circle, it's necessary to use the number pi, which is represented by the symbol π. You can use the decimal 3.14 to represent the value of pi. The formula to calculate the square footage of a circle is:

A = π x radius2

In this equation, "A" is the total square footage, π is equal to 3.14 and the radius is the distance from the exact center of the circle to the outside edge in feet. To calculate the area of a circle, use the following steps:

  1. If it isn't already in feet, convert the measurement for the radius into feet.

  2. Multiply the length of the radius by itself to get feet squared.

  3. Once you've calculated the square feet of the radius, multiply that result by pi to get the total area of the circle in square feet.

How to calculate square feet for trapezoids

To calculate the square footage of a trapezoid, you can use the formula:

A = [(base length + top length) / 2] x height

In this equation, "A" is the total area of the shape in square feet. The base length is the length of the bottom of the trapezoid in feet, and the top length is the length of the top of the trapezoid in feet. The height is the vertical distance from the base length to the top length of the trapezoid in feet. You can use the following steps to calculate the area of a trapezoid:

  1. If necessary, convert the measurements for the base length, top length and height into feet.

  2. Add the base length and the top length together to calculate the area for the nonrectangular sections of the trapezoid created by the diagonal sides.

  3. Divide the sum of the base length and the top length by two to ensure you account for the diagonal sides in the equation.

  4. Multiply that result by the height to find the area of the trapezoid in square feet.

Related: Rules of Multiplication: Definition and Examples

How to calculate square feet for rhombuses

To calculate the square footage of a rhombus, you can use the following formula:

A = distance from one pair of opposite angles x distance from the other pair of opposite angles

In this equation, "A" is the area of the rhombus in square feet and the distances from both pairs of opposite angles are in feet. You can calculate the area of a rhombus using the following steps:

  1. Convert the measurements for the distances of the rhombus into feet if necessary.

  2. Multiply the interior lengths, which are the distances from opposite angles within the rhombus, to find the area in square feet. The interior lengths intersect with each other at the center of the shape.

How to calculate square feet for parallelograms

To calculate the square footage of a parallelogram, you can use the formula below:

A = base x height

In this equation, "A" is the area of the parallelogram in square feet, the base is the length of the bottom side of the parallelogram in feet and the height is the vertical distance from the base of the parallelogram to the top side in feet. You can calculate the square footage of a parallelogram using the steps below:

  1. If necessary, convert the measurements for the base and height into feet.

  2. Multiply the base by the height of the parallelogram to find its area in square feet.

When in doubt, ask the pros

If calculating the square feet of your particular property feels overwhelming, consider hiring a professional appraiser to do it. The average appraisal cost for a single-family home typically runs about $350. A condo appraisal fee is generally between $300 and $500, and multi-family home appraisals can run anywhere from $600 to $1,500.

While two different professional appraisers could evaluate the same home and come up with slightly different square footage figures, they do all aim for scientific accuracy. “We’re always shooting for somewhere between 1 to 3 percent variance,” Day says.

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