Why square footage is important

There are plenty of reasons you might want to know how to calculate the square feet of a house, whether you’re looking to sell a property, dispute a high tax assessment or renovate to add more space.

If you’re preparing to list your home for sale, determining the property’s exact size is a crucial factor when setting your asking price. “For a home appraisal, we’re going to compare it to comparables or ‘comps,’” says Day, who looks for homes of similar size in the immediate area. An inaccurate square footage measurement could potentially result in an inaccurate appraisal price.

Square footage (often abbreviated as SF or SQFT) also matters in real estate deals that involve a mortgage, for similar reasons. The lender will want that info to verify what the property is worth.

However, knowing your home’s square footage can come in handy in other ways as well. For instance, if you decide to finish a previously unused part of your house — say, a basement or attic space — you may need to provide the square footage to obtain a building permit.

Likewise, if your county or municipality assesses higher taxes than what you think you should owe, confirming the square footage can be a point in your favor toward getting the property taxes reduced.

How to quickly estimate square footage

Sometimes, you might need to estimate or visualize square footage without being able to measure it exactly. This is an especially useful skill if you’re shopping for a home or apartment. Here are some tips, tricks, and examples for making square footage estimates in the real world.

Use your body

One way to get a rough estimate of the width and length of a space is by using your own body. Measure body lengths to use your height. Or measure the length of your foot and walk heel-to-toe to measure the distance. You can also measure the length of your stride, but this will result in a less accurate measurement, since it will vary a little bit with each step.

Use tiles

If the room you’re trying to estimate has tiles on the floor, you can use them to get an estimate of the square footage by assuming that each tile will be around one square foot. Remember that tiles can be larger or smaller than this, though, so your accuracy may vary with this method depending on how close the tiles are to 12 inches.

Visualize comparative spaces

If you don’t need an exact number, but just a rough guess of the square footage of a space, you can compare it to items or other spaces you might be familiar with. For example,

  • A king size bed is 42.15 square feet.
  • The inside of a school bus is about 300 square feet.
  • A one-car garage is about 200 square feet, while a two-car garage will be around 400 square feet.




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).


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.

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.

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

Calculate square footage (sq ft) from other units

Let’s now see how to calculate square footage when you already know the area in different units. This is the most simple use of the square footage calculator. To use this conversion feature, you could use the area conversion tool on this website or simply follow the following steps:

  1. In the square footage calculator find the Area tab and select units you want to convert from,
  2. You can now enter the value of the area in those units,
  3. Click again on the unit switcher and select square feet (sq ft),
  4. Automatically, the calculator will show the value in sq ft.

  It is also possible to convert in the other direction by applying this method, i.e., from a different unit, like square meters to square feet. We will now show some examples of conversions to and from square footage.

How to calculate square footage? 

It’s easy.  Follow these steps.

Measure the length in feet, Measure the width in feet. Multiply the length figure by the width figure.  This will be your total square footage for that portion of your project.  Continue to repeat this for all parts of the space that will get the same tile.   Add these together for your total square footage.

Measuring in inches works as well.  Do the math the same way, then divide by 144 to get your total in square feet. When calculating square footage account for the entire space (i.e. under vanity/cabinets).

How to measure the square footage of a house or property

We have touched previously on how to calculate and measure square footage in a simple situation like a rectangular room/house or a circular and triangular… But there are situations in which the shape of the property we want to measure square footage from, is a bit more complicated than that. In those cases there are two options: (1) using the area of a polygon calculator and other similar calculators by Omni (we can recommend the hexagon / octagon area calculators or (2) get creative, as we’re gonna do now.

For very complicated and irregular shapes, there is no simple recipe for how to measure the square footage of a house using just one tool. However, we can use a simple trick to achieve the appropriate result. We can try to decompose the area into several small pieces that have a regular shape, for which we can calculate square footage. To each of those pieces, we apply the square footage formula corresponding to its polygonal shape (different Omni Calculators will prove useful here). If we then add up the result from every piece, we will obtain the total square footage of the house, no matter its shape.

There is a chance that the house will have rounded corners of curvy shapes (they are very popular nowadays), and this might seem impossible to do. But in reality, one can get a very good approximation using a straight line that goes to the middle of the curved ones or, if we want to be more precise, many small polygons. It could be time-consuming, but it simultaneously can be as accurate as one needs.

The importance of knowing square footage

What’s the big deal about square footage, anyway? Why is it so hard to calculate — and so important to know?

Square footage is a necessary piece of data for determining a number of things about your home and your family’s needs. These are just some of the reasons it’s so important to know and understand square footage.

Home value and price per square foot

First and foremost, square footage is a major factor in determining your home’s value. Generally, when appraising a home, professionals will first calculate the exact square footage, and then compare your home to other homes in the same area with a comparable amount of living space.

They’ll make adjustments based on factors like your home’s age, materials, and finishes — but square footage is the single most important factor (and the first step) in setting a value or sale price for your home. Additionally, being familiar with the price per square foot for your home and similar, nearby listings can give you a point of reference for comparing different properties when shopping for a home.

This is also one of the reasons it’s so important to get an accurate measurement of your home’s square footage — if it’s measured incorrectly, that can have a domino effect that throws off your home’s value, sale price, and more.

Home renovation costs

If you ever make any major updates to your home — for example, renovating your kitchen or finishing your basement — you’ll likely need to know the exact square footage in order to get building permits.

Knowing the exact square footage of a space you’re renovating is also helpful when it comes to making cost estimations and setting a budget for the project. Different areas, like kitchens, bathrooms, and basements, have different average costs per square foot to renovate, so familiarizing yourself with these can help you set a realistic budget for making over your own space.

Property taxes

Since square footage is such an important factor in your home’s value, it’s also a big part of determining your yearly property taxes, which are based on the assessed value of the home and property. If your square footage is improperly calculated, it could result in you over- or under-paying on your taxes.

Additionally, if you work from home, knowing your home’s square footage can help provide tax benefits — you may be able to write off a portion of your rent or mortgage payments and utilities based on the square footage of a home office or work area.

Knowing your (and your family’s) needs

Finally, knowing and understanding square footage can help you better understand exactly what your family needs when looking for a home. We’ll get into this in more detail below, but it’s always a good idea to know how much square footage your family needs to live and function comfortably.

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.

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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