Square Footage Calculator
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Our calculator helps you estimate the area and material requirements for rooms, roofing, flooring, carpets, walls, pools, lawns, heat pumps and more. You can also estimate the cost of materials involved in the project by entering a price-per-square-foot.
Continue scrolling down for instructions on how to manually calculate square footage, with formulas and example calculations.On this page:
How to calculate square footage
If you're looking to install new carpet or flooring in a room, or work out what materials you require for a garden or construction project, you'll need to know how big the area is. This will help you accurately assess the amount of flooring, carpet or materials required for the project.
To calculate the square feet area of a square or rectangular room or area, measure the length and width of the area in feet. Then, multiply the two figures together: Sq ft = Length (ft) × Width (ft).
Feet to square feet - explanation
The foot is a unit of length, and the square foot is a unit of area. When converting measurements from feet to square feet, you are essentially determining the area of a two-dimensional space. To do this, you need two length measurements (both in feet) – one for the length and another for the width. Once you have these measurements, you can simply multiply them together to obtain the area in square feet:
Square footage = Length (feet) × Width (feet)
To give an example, if a bedroom measures 16 feet by 12 feet, the calculation would be 16 multiplied by 12, resulting in a square footage of 192 (16 × 12 = 192).
Once you have your square footage figure, you can work out what materials you might need. We have an article covering how to measure for flooring or carpet for a room or house, if you need it.
Of course, it may be that your room or area is 'L' shaped. In which case, the process requires a little extra thinking...
Calculations for 'L' shaped rooms or areas
To calculate the square feet of an 'L' shaped room or area, divide the shape up into rectangular sections and treat each one as a separate area for calculation. You can then add the totals together at the end.
In the example image above, we have divided our 'L' shaped area up into two sections. The first section measures 6ft × 5ft = 30 square feet. The second section measures 14ft × 10ft = 140 square feet. Adding the two figures together we find that our area measures 30 + 140 = 170 square feet.
It's worth noting that we have a step-by-step guide for how to measure and calculate square footage for home improvement projects, which discusses this process in more detail.
How to calculate square footage for walls
To calculate the square footage of a wall, follow these simple steps:
- Measure the height of the wall from the floor to the ceiling, excluding baseboards and moldings.
- Measure the length of the wall, including doors and windows.
- Multiply the height by the length to find the total square footage of the wall.
- For a more accurate calculation, measure and subtract areas that are not covered, such as windows, doors and closets.
By following this process, you'll have an estimate to help you calculate the amount of materials needed to paint or wallpaper your wall.
How to calculate the square footage of a house
There are many reasons why you might want to calculate the square footage of a house. Perhaps you want to assess a property's value, plan home improvements, evaluate insurance coverage or prepare for installing a new heat pump. So, what is the most effective method for calculating how big a house is?
If your house is a perfect rectangle then you can roughly calculate the square footage by measuring the width and length of the house and multiplying the two figures together. This will give you the square footage of each floor. If your house has multiple levels, calculate the square footage for each level separately, and then add them together to obtain the total square footage of the entire house.
Of course, it may be that your house isn't a perfect rectangle. Or, you may wish to only calculate the total square footage of the living space in the house. In this case, you can try the following process:
- Create a floor plan: Draw out a floor plan of each level of your house.
- Measure individual rooms: Measure the length and width of each room within the house. Make sure to measure from wall to wall, excluding any non-living spaces like closets.
- Multiply length by width: For each room, multiply the measured length by the width. This will give you the area of each room in square feet.
- Add up the room areas: Add together the square feet measurements of all the individual rooms to get the total square footage of living space in the house.
For living space calculations, consider including and excluding the following from your calculations: 2
- Include: Common areas such as hallways, staircases, closets, and foyers.
- Exclude: Non-living spaces like garages, unfinished basements, and utility rooms, as they are not typically considered part of the living space.
Edina Realty has a good article on what to include/exclude, if you want some more clarification.
Here's a video example of how to draw out a floor plan to calculate the square footage of a house...
It's important to note that this is a general approach for calculating square footage, and there may be specific considerations or variations based on local building standards or regulations. If you want an accurate measurement, it's worth seeking professional assistance from an appraiser or architect.
The median size of a single family house in the United States is 2,261 square feet, according to Statistica. 1
Other shaped areas
It may be that the area you're looking to calculate is a triangle or circular shape. So, let's quickly cover how to calculate square footage for these shapes:
Square footage of a triangle
Here's how to calculate the area of a triangular-shaped area:
- Measure the length and the width of the triangle in feet.
- Multiply your length and width measurements together.
- Divide your total by two to get the square footage of the triangle
Square footage of a circle
Here's how to calculate the area of a circular-shaped area:
- Measure the diameter of your circle in feet.
- Divide your diameter by 2 and then square it (multiply it by itself).
- Multiply your total by π (3.14159265)
If you're calculating a square feet measurement for a garden or construction project, consider making use of some of our other tools to calculate cubic yard volume for bulk materials, such as mulch or gravel.
Summary of calculations
Here's a summary of what we've covered:
|Sq. ft Calculation (in feet)|
|Rectanglar room/area||Width × Length|
|L-shaped room/area||Split the area or room into separate rectangles and measure each separately|
|Wall||Height × Length (then subtract windows, doors and closets)|
|Triangular room/area||Length of base × Height / 2|
|Circular room/area||π × [Diameter / 2]²|
If you want to work out a cubic feet volume based upon your square feet figure, you can try our square feet to cubic feet calculator. For further assistance with measuring and calculating square feet for a room or house, check out our step-by-step guide.
And, if you're measuring land, we have a handy tool to help you convert between acres and square feet.Calculator by Alastair Hazell
- Statistica. Median size of single family housing unit in the US from 2000 to 2020.
- Edina Realty, Inc. What’s included in square footage of a house?.