How to Figure Out the Square Footage of a Home

Definition of Square Footage

Square footage is a measurement of area, and area is the measurement of any two-dimensional space contained within a set of lines. Think of it in the sense of a dance floor. Take a moment to imagine a dance floor that is 20 feet by 20 feet (6.09 meters by 6.09 meters). How do we express the area that it takes up? This one is easy, because the dance floor is a square. We simply multiply the width of the floor by the length of the floor, 20 feet times 20 feet equals 400 square feet. Therefore, the total area of the dance floor is 400 square feet (37.2 square meters). The equation is the same for a rectangle [source: MCWDN].

Area of a square or rectangle = Width x Length


It’s important to keep in mind that a square foot doesn’t necessarily have to be shaped like a square. The dance floor above could be shaped like a triangle and cover the same amount of area. If you were asked to determine the area of a triangle or a circle, the equation would be different, but the concept is the same. Plug in the right numbers and you’ll get the right answer. Both equations are listed below.

Area of a triangle = ½ (Base x Height)

Area of a circle = 3.14 x radius2

So we’ve established that the square in square feet doesn’t refer to shape. All measurements of area are expressed in square units — the standard foot just happens to be the unit used in U.S. real estate.

Read on to find out how to calculate the square footage of a house.

It’s Hip to Be Square­­ Most houses are shaped like rectangles or squares, which makes calculating the square footage easy, whether you’re measuring outside or inside the home. But what if you need to measure inside a house that has an odd number of walls and corners that aren’t 90 degrees? That doesn’t have to be difficult either. Just break it down into smaller rectangles, squares and triangles. Then determine the square footage of each individual section and add them together.


How to Figure Out the Square Footage of Non-Rectangular Rooms

If you have a room that’s not a perfect rectangle – maybe it has a square area attached – just divide it into separate rectangles, calculate the square footage for each of them, and add up their totals like you would with the rest of your house.

However, some homes have areas that aren’t rectangular.

How to Figure Out the Square Footage of a Semicircle

For example, you could have a semicircle coming off of a room to give a panoramic view of the surrounding area.

In that case, measure the line that makes up the straight portion of the semicircle.

Then, divide it by two, so you have the radius (r).

Plug that number into the equation for a circle’s area: πr2.

Finally, divide the answer by two.

So, if you measure the straight line and it equals 10 feet, you’d divide that by 2, getting 5 feet.

After you square 5 feet, you’d have 25 feet and then, multiplying it by π, you’d arrive at 78.54 feet. Divide that by 2 and you have your square footage for the semicircular space: 39.27 feet.

How to Figure Out the Square Footage of a Triangular Space

Does the house in question include a triangular space?

In that case, turn the triangle into a right triangle by starting at the tallest point and cutting it down the middle (if it’s already a right triangle, skip that step).

Then, multiply the height by the base and divide that number by two. That’s it. That’s the square footage of the triangular space.

If you had to cut your triangle in half, just find the square footage for both and add them together.

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 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 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.

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 Inches
    • multiply ft2 by 144 to get in2
  • 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 Inches
    • multiply m2 by 1,550 to get in2
  • 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

How many square feet is a 20×20 room?

The square footage of a room measuring 20 feet wide by 20 feet long is 400 square feet. To calculate this you simply multiply the width by the height. 20ft × 20ft = 400 sq ft.

4. What is Net Cleanable Square Feet?

Net Cleanable Square Feet (“NCSF”) is the sum of all floor area that requires custodial services. NCSF is a great metric to know, especially for your facility’s custodial personnel. Having accurate NCSF measurements can help determine custodial staffing, inform budgeting and aid in service provider solicitation.Custodial budgets will realistically contain chemi

Custodial budgets will realistically contain chemicals, paper supplies, equipment and custodial labor costs to get the job done. Not knowing your facility’s true NCSF might mean that you are budgeting too little or too much for cleaning. If you want to learn more about custodial budgeting and planning for your facility teams, check out our free guide on creating a custodial cleaning plan.

How to Calculate Net Cleanable Square Feet

Determine the square footage of each room that needs to be cleaned. Areas that require no cleaning, such as closet areas and mechanical rooms, should not be included. Once you’ve gathered square footage (minus non-cleanable areas) for all rooms, add them together. This number is your total square footage that needs to be cleaned.

You can take this process a step further and add cleaning costs to the equation. Multiply total cleanable square footage by a base price for cleaning. For instance, if your total area to be cleaned is 5,000 square feet and the price per square foot is 25 cents, you can multiply $0.25 times 5,000 to get a total of $1,250 for cleaning fees.

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.

Square feet to cubic feet

If you would like to convert your square footage into cubic feet, take a look at the square feet to cubic feet calculator.