Square Footage Calculator
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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 to find the square footage of a rectangle
- Measure the width and length of the area in feet.
- Multiply your length and width together to get your area.
Note: If your measurements aren't in feet, convert them to feet first using our length converter.
Once you've carried out your calculation, you will have your square feet (ft2) figure. To calculate your cost of materials, simply multiply this figure by your price per square foot.
How to find the square footage of a triangle
- Measure the length of the base and the height of the triangle in feet.
- Multiply your base and height measurements together.
- Divide your total by two to get the square footage of the triangle
The formula for calculating the square footage area of a triangle is: base × height / 2. To work out your cost of materials, simply multiply this figure by your 'price per square foot'.
How to find the square footage of a circle
- 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)
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 20x20 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.
How many square feet is a 12x12 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.
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.