How to Calculate Square Footage

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 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.

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.

What is square footage used for?

You can use square footage in real-world contexts such as:

  • Architecture: Architects use square footage to measure the space that a building or other construction projects may fill.

  • Cartography: Cartographers use square footage to determine the area that countries and other landmarks might occupy on a map or globe.

  • Landscaping: Landscapers use square footage to find how much space a yard or other plot of land takes and what can fit within that space.

  • Real estate: Realtors and contractors use square footage to describe how much floor space a house or other marketable building has when it's for sale.

You can also use square footage as the first step toward calculating cubic footage, or the volume of an area. For example, you can use the outcome of the calculation and multiply the number by the width of a shape. If the measurements are in feet, then you get a cubic measurement. This means there are three sides you measure to get the volume of the shape.

Related: Top Skills Required for Landscaping

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.

How to measure for bullnose?

Measure the length of any outside edge where your tile edge would be exposed or you want framed out.  Bullnose (also called trim pieces and decorative tiles) are typically sold by the piece. To figure the quantity you have to establish the length of the trim piece (i.e. 6″ bullnose, 8″ decorative liner), then the rule is:  Your total linear length divided by the length of each piece equals your quantity needed.  

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 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.

How to Clean a Glass Stovetop

Smooth glass stovetops are great appliances. But even small specks or spills can stand out on the surface.…

Read More