How To Calculate The Square Footage Of A Home

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Enter lineal feet and the material width to calculate the total square footage of material. If you know how many square feet of material, enter that and the material width to convert to lineal feet.

How to calculate the square footage 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.

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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.

How to find the square footage of a triangle

  1. Measure the length of the base and the height of the triangle in feet.
  2. Multiply your base and height measurements together.
  3. Divide your total by two to get the square footage of the triangle
 The formula for calculating the square footage ar

The formula for calculating the square footage area of a triangle is: base × height / 2. To work out your cost of materials, simply multiply this figure by your 'price per square foot'.

How to calculate how many pieces of bullnose you will need?

If you have ten feet exposed edge that needs bullnose this is equal to 120″.  If you selected a 6″ bullnose or trim piece, you will need to divide 120″ by 6″, which will give you 20 pieces of bullnose needed.  Using 8″ decorative liner for the same 120″, you divide 120″ by 8″ which would be 15 pieces of liner needed.

Determining the Size of Area

Step 1: Inspect the Area

The first piece of information you need to know is the shape and dimensions of your lawn, particularly the width and length. You will want to measure and multiply the area length times the width in feet until the square footage is 1,000 sq. ft. and mark off this area with the help of a marking tool like washable paint or objects to distinguish the treatment areas border line. 

Step 2: Convert Measurements

If your yard is rectangular or square, measure the length and width then multiply together (length X width = square footage). For example, if your yard has a length of 10 feet and width of 8 feet, you would multiply 10 by 8 to get 80 square feet.

Be aware for triangle shaped lawns, you will measure the length and width, multiply together, then divide by two ( length X width / 2 = square footage).

If your lawn is a not a perfect rectangle, break the lawn into different sections to measure more easily, then add measurements together to get the area’s total square footage.

For treatment areas with flowerbeds and other obstructions in the yard you will measure the square footage of the object and subtract from your yards total square footage.

Example, you have a property that is 12,000 sq. ft. and in the middle you have a landscape bed with a length of 3 feet and width of 2 feet. You will multiply 3 by 2 to get 6 feet, then subtract from your yard total.

  • 3 ft. X 2 ft. = 6 sq. ft. 
  • 12,000 sq. ft. – 6 sq. ft. = 11,994 sq. ft. 

Therefore, you will treat an area with 11,994 sq. ft. 

How much to allow for waste?

To allow for waste, you must consider the installation.  For most standard installations, 10% extra for waste is sufficient.  Percentage of waste for more elaborate patterns like running tile on a 45 degree angle, herringbone or cross hatch, consult with your installer. Add 15% for tile being installed in a room with lots of jogs and corners. These installations will require more cuts and thus more waste.

Length x Width + Waste = Amount Needed

How many square feet is a 12×12 room?

The square footage of a room measuring 12 feet wide by 12 feet long is 144 square feet. To calculate this you simply multiply the width by the height. 12ft × 12ft = 144 sq ft.

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.

How to Calculate Square Footage

Square footage is area expressed in square feet. Likewise, square yardage is area expressed in square yards.  Square meters is also a common measure of area.

Assume you have a rectangular area such as a room and, for example, you want to calculate the square footage area for flooring or carpet.

The way to calculate a rectangular area is by measuring the length and width of your area then multiplying those two numbers together to get the area in feet squared (ft2). If you have on oddly shaped area, such as an L-shape, split it into square or rectanglualar sections and treat them as two separate areas. Calculate the area of each section then add them together for your total. If your measurements are in different units, say feet and inches, you can first convert those values to feet, then multiply them together to get the square footage of the area.

Convert all of your measurements to feet

  • If you measured in feet skip to “Calculate the Area as Square Footage”
  • If you measured in feet & inches, divide inches by 12 and add that to your feet measure to get total feet
  • If you measured in another unit of measure, do the following to convert to feet – inches: divide by 12 and that is your measurement in feet – yards: multiply by 3 and that is your measurement in feet – centimeters: multiply by 0.03281 to convert to feet – meters: multiply by 3.281 to convert to feet

Calculate the Area as Square Footage

  • If you are measuring a square or rectangle area, multiply length times width; Length x Width = Area.
  • For other area shapes, see formulas below to calculate Area (ft2) = Square Footage.

Square Footage Formulas and Images for Different Areas

Using measurements in feet: Area (ft) = Side Length x Side Length

Using measurements in feet: Area (ft) = Length x Width

Using measurements in feet: Inner Area (ft) = Length x Width Total Area (ft) = (Length + (2 x Border Width)) x (Width + (2 x Border Width)) Area (ft) = Total Area – Inner Area

Using measurements in feet: Area (ft) = Pi x (Diameter/2)^2 Pi = 3.14

Calculate square footage for a circle border area Using measurements in feet: Outer Diameter = Inner Diameter + (2 x Border Width) Outer Area (ft2) = Pi x (Outer Diameter/2)^2 Inner Area (ft2) = Pi x (Inner Diameter/2)^2 Area (ft2) = Outer Area – Inner Area Pi = 3.14 Obviously, the Circle Border and Annulus are the same, just measured differently.

Calculate square footage for a annulus area Using measurements in feet: Outer Area (ft2) = Pi x (Outer Diameter/2)^2 Inner Area (ft2) = Pi x (Inner Diameter/2)^2 Area (ft2) = Outer Area – Inner Area Pi = 3.14 Obviously, the Circle Border and Annulus are the same, just measured differently.

Using measurements in feet: Area (ft) = (1/4) x square root[ (a+b+c) x (b+c-a) x (c+a-b) x (a+b-c) ]

Using measurements in feet: Area (ft) = ((a + b) / 2 )h

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