How to Accurately Calculate Square Feet for Any Space
Key Takeaways:

Introduction to Measuring Square Feet
As you begin your homebuilding or real estate journey, there are likely hundreds of different numbers running through your head. Your mind may feel like a looping reel of costs, budgets, measurements, and formulas. It can feel overwhelming, but it helps to know what numbers to prioritize first. One of the first things you should learn when starting your build is how to calculate the square footage of a house.
Square footage is calculated by multiplying the length of the space by its width. For example, if a room is 9 feet long and 10 feet wide, its area is 90 square feet. Before we dive into different steps, tips, and tricks for calculating the square feet of any area, you should first know the importance of measuring square footage.
Why Calculating Square Footage is Important
Knowing how to calculate the square footage of a home is a very beneficial skill to have in the process of home building and will come in handy in many scenarios, including

Determining the real estate value of your home: Square footage is a key factor in determining the value of a home. Should you ever choose to sell your home, this information will be crucial for appraisers, buyers, and real estate agents.

Buying and installing flooring: When it comes time to buy flooring (or make renovations), you will need the square footage of the area you are working on in order to buy the correct amount of materials.

Paying property taxes: If you live in an area where real estate property taxes are assessed based on the square feet of a house, knowing the number will help ensure that you are paying the correct amount in property taxes.

Obtaining building permits: In most areas, you will typically need to submit plans that show the square footage of your home in order to obtain a building permit.

Purchasing insurance: You will need to provide the square footage of your home to insurance companies for the majority of policies. This information is also used to determine the cost of your premium.

Home improvement projects: If you eventually decide to add an addition onto or update your house, you will need to know the sq ft. This information will be especially useful if you go the “diy” route and make renovations yourself, without the help of a professional.
Tools Needed for Accurate Measurements
The exact measuring tools you need to measure the square feet of a room will depend on the shape of the room. In general, you will need:

Tape measure

Measuring wheel

Laser distance measurer
Additionally, some websites offer free square footage calculators for your convenience.
Required Steps for Measuring Square Feet
The size and shape of a room determines the best way to approach measuring an area. Here, we will walk you through how to measure different spaces in your home.
Irregular shapes
To measure the sq. ft of an oddshaped room, or a room with nooks, closets, or alcoves, follow these steps:

Divide the room into smaller, regular shapes, such as rectangles or triangles.

Measure the length and width of each shape using your tape measure, measuring wheel, or laser distance measurer.

Calculate the area of each individual shape by using the square footage formula, multiplying the length x width.

Add up the areas of all the shapes to find the total square footage of the room.
Tips for calculating the square footage of an irregular shape:

When dividing the room into multiple shapes, make sure that the shapes are completely enclosed and that there are no gaps between them.

When calculating the total area of each shape, round each number to the nearest square foot.
Rectangular areas
To measure the sq. ft of a rectangular room, follow these steps:

Measure the length of the room by starting at one corner of the room and extending the tape measure to the opposite corner. Record the measurement in feet.

Measure the width of the room by starting at the same corner where you measured the length and extending the measuring tape to a different corner on the same wall. Record the measurement in feet.

Multiply the length by the width to calculate the square footage.
Tips for calculating the square footage of a rectangular area:

Always measure the longest and widest dimensions of the room.

If the room has any obstacles, such as a closet, measure around them.

Round the square footage measurement to the nearest square foot.
Small and large rooms
To measure the square footage of small and large rooms, follow the above steps depending on the shape of the room. For small rooms, a tape measure is a great tool to use in the process. You will likely want to use a laser distance measurer for a larger room.
What is Usable Square Footage?
During the process of your home build, you may see the term “usable square footage” pop up. When it comes to a singlefamily dwelling, usable square footage refers to the finished area of a home that is accessible by people and can be heated. Generally, usable square footage does not include unfinished spaces, such as garages, basements, and attics, unless they have been finished and converted into living space. Decks, porches, and patios are also exempt from usable square footage.
RealLife Examples
Measuring square footage involves determining the total area of a space or surface in square units. Here are some reallife examples:

Living Room:

Situation: Imagine you want to install new carpeting in your living room.

Method: You'd measure the length and width of the room. For instance, if your living room is 15 feet in length and 20 feet in width, you'd calculate the area by multiplying these two numbers.

Outcome: You'd need 300 sq ft of carpeting for your living room.


Floor Plan:

Situation: Consider you're a homebuyer looking at a floor plan of a house. The floor plan shows the dimensions of each room.

Method: To determine the total living area of the house, you'd need to calculate the area of each room and then sum them up. For instance:

Living room: 20 ft by 15 ft = 300 sq ft

Kitchen: 10 ft by 8 ft = 80 sq ft

Bedroom: 12 ft by 12 ft = 144 sq ft

Bathroom: 8 ft by 5 ft = 40 sq ft


Outcome: Adding these areas together gives you a total living space of 564 sq ft.


Landscaping:

Situation: Imagine you want to plant grass on a section of your yard, and you need to determine the amount of sod required.

Method: Measure the length and width of the area where you want the grass. Suppose the area is rectangular and measures 25 ft in length and 10 ft in width.

Outcome: You'd need sod to cover 250 sq ft of your yard.

Keep in mind that these examples are simplified and based on perfect rectangles. Reallife spaces might have irregular shapes, so you'd divide them into simpler shapes (like rectangles, triangles, etc.) to calculate the total area.
Common Mistakes and How to Avoid Them
While measuring the square feet of an area is a simple formula, it is easy to make a mistake that will affect your calculations. There are some common mistakes to avoid when working on your project:

Making inaccurate measurements: Even a small error in measurement can make a big difference in the square footage calculation. You will want to be sure to use the proper tools when measuring sq. ft, mark off spots as needed, and round up to the nearest foot.

Misunderstanding the difference between usable square footage and total square footage: As discussed above, usable square footage is the total finished area of a space that can be used by the occupants. Total square footage is the total area of a space, including common areas and unfinished space. When measuring the square footage of your home, it is important to specify whether you are measuring usable square footage or total square footage.

Measuring irregular shapes incorrectly: If a room has an irregular shape, such as a bay window, closet, fireplace, or alcove, it is important to divide the room into smaller, regular shapes and measure each shape individually. Then, add up the areas of the individual shapes to get the total square footage of the room.
FAQs:

What tools are essential for measuring square footage?
A tape measure, a laser measurer, and a measuring wheel are all essential tools for measuring square footage.

How do you calculate square feet for triangular or circular areas?
To measure the square footage of a circular area, you will need the radius of the circle. The radius is the distance from the center of the circle to the edge of the circle. You will then use this formula to determine the square feet of the area: Square footage = π radius^2.
To measure the square footage of a triangular area, you will need to know the base and height of the triangle. The base is the longest side of the triangle, and the height is the perpendicular distance from the base to the opposite vertex of the triangle. From there, use the following formula to determine square feet: Square footage = 1/2 base * height.

Are there apps or tools online that can assist with these calculations?
There are many apps and tools available online that will assist with accurately measuring square footage. 
How do I convert square feet to square meters?
The formula to convert square feet to square meters is: square meters = square feet * 0.0929. 
What's the difference between square feet and cubic feet?
Square feet is a unit of area, which is the twodimensional extent of a surface. It is calculated by multiplying the length of the surface by its width. Cubic feet is a unit of volume, which is the threedimensional extent of an object. It is calculated by multiplying the length of the object by its width by its height. 
How do I calculate the square footage of a room with a sloped ceiling?
To calculate the square footage of a room with a sloped ceiling, you will need the length, width, and height of the room. You will also need to know the ceiling height at the lowest point and the ceiling height at the highest point. Once you have this information, use the following formula to calculate the square footage of the room: Square footage = (length + width) / 2 * (height at lowest point + height at highest point) / 2.
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Resources:

Rivelli, E. (2023, January 14). How to calculate the square footage of a home (and why it’s important). Bankrate. https://www.bankrate.com/realestate/determinesquarefootageofhome/#calculate

Thorsby, D. (2023, June 14). How to measure the square footage of a house. US News & World Report. https://realestate.usnews.com/realestate/articles/howtomeasurethesquarefootageofyourhouse#:~:text=Tools%20You'll%20Need%20to%20Measure%20Square%20Footage&text=Tape%20measure.,Calculator.

Akirov, R., & Akirov, R. (2022, December 5). How to figure out the square footage of a room. Rhodium Floors. https://rhodiumfloors.com/blog/howtofigureoutthesquarefootageofaroom/#:~:text=The%20easiest%20way%20to%20calculate,their%20lengths%20by%20their%20widths.

Irene. (2023, October 11). How To Calculate Square Feet of Your Property: Ultimate Guide. Chekin. https://chekin.com/en/blog/howtocalculatesquarefeetofyourpropertyultimateguide/

The importance of square footage. (n.d.). https://www.nationalfloorplans.com/squarefootageimportance

Somers, J. (2023, October 16). Why Knowing how to calculate square feet is essential for home improvement projects  Crest Real Estate. Crest Real Estate. https://www.crestrealestate.com/calculatesquarefeetimportance/#:~:text=Before%20diving%20into%20any%20home,informed%20decisions%20about%20optimizing%20them.