How to Calculate Square Feet

How to calculate square feet :Square feet of an area is determined by multiplying length and the width of the given area . The area of regular polygons like square , rectangle , triangle etc... can be calculated by using the formula . If the dimensions of a regular polygon is given in feet then by just substituting the given dimensions in the formula the area in square feet can be calculated , if the measurements are given in any other units such as centimeter or inches or yards then we convert these units to feet and then calculate the area in square feet , similarly for a circle also if the radius is in feet we can just substitute the radius in the area formula and calculate the area in square feet ,if the radius is given in any other unit then convert that to feet and then calculate the area in square feet .

Area of composite shapes , a composite shape is a shape which can be divided into more than one of the basic shapes . An example of a composite shape or figure is shown in the picture .

Here in this picture we can see a square , a rectangle and a triangle . Area of the whole figure can be calculated by calculating the areas of each shape and then adding them . If the measurements are not in feet then we have to convert them to feet and calculate the area in square feet .

How to calculate square feet live situations .

The home we live , the school we study and mostly all other places one or the other time needs the area of floors , walls, ceilings , windows etc. in square feet to get them painted or any other purpose and usually the areas are calculated in square feet as most of the paints or coating materials have the coverage  specification mentioned in square feet like a ' x ' brand paint covers 30 square feet per liter . 

For How to calculate square feet the example here is an interior view of a room which has to be carpeted and walls painted .( all measurements are in feet )

We can see a room with a floor plan of a 

composite figure , that can be split into two rectangles as shown.

                                                          

Area of the floor in square feet to be carpeted is calculated by first learning How to calculate square feet :

Area of the floor  =  Area of rectangle 12 x 8  +  Area of rectangle 9 x 6

Area of the floor  =  96 square feet  +  54 square feet

Area of the floor  =  150 square feet .

There are all together six rectangular shaped walls as shown below .( figures not to scale )

To find the  total wall area , find the area of each wall and add them up .

   

  Area of wall 1. = ( 10 feet x 8 feet ) - ( 7 feet x 3 feet ) [ area of door ]                                                =   80 square feet  -  21 square feet  =  59 square feet

   Area of wall 2. = 10 feet  x  12 feet  =  120 square feet

   Area of wall 3. =  ( 10 feet x 14 feet ) - ( 4 feet x 5 feet ) [ area of window ]                                       =    140 square feet  -  20 square feet  =  120 square feet

   Area of wall 4. =  10 feet  x  9 feet  =  90 square feet

Area of wall 5.  =  10 feet  x  6 feet  =  60 square feet  ,  Area of wall 6.  =  10 feet  x  3 feet  =  30 square feet 

Total area of the wall to be painted  =  59  +  120  +  120  +  90  +  60  +  30  =  479 square feet .

How to calculate square feet unit conversion examples .

How to Calculate square feet  in each diagram .



The dimensions given for this square is in inches , we have to convert the inches to feet so that we can calculate the area in square feet .
12 inches = 1 feet  so   24 inches = 2 feet
Area of square is given by  A  =  s²       where  s  =  2 feet
Area of square  A  =  ( 2 feet )²      =    4 square feet

The dimensions for this triangle are in centimeters , we have to convert centimeters to feet so that we can calculate the area of triangle in square feet .
30 cm = 1 feet    and   15cm = 0.5 feet
Area of triangle is given by  A  =  1/2 b h  ,   where base b = 0.5 feet and height h = 1 feet
Area of triangle  A  =  1/2 x  0.5 feet  x  1 feet  =  0.25 square feet


This a composite shape and we have split that into basic shapes , we have two rectangles , one triangle and a semi circle.
Area of the total shape = 4 x 5 + 4 x 9 + 1/2 x 4 x 4 + 3.14 x 2²                                                                                                                   2
Area = 20 + 36 + 8 + 6.28  =  70.28 square feet


The radius of the circle is given in meters , we have to convert the meters to feet so that we can calculate the area of circle in square feet .
1 meter  =  3 feet   so   3 meters  =  9 feet
Area of circle is given by   A  =  π r²       ,    where     =  3.14 ,  radius r  =  9 feet
Area of circle  A  =  3.14  x  9²    =  3.14   x  81  =  254.34 square feet

Students can learn How to calculate square feet from the above examples and solve problems on similar lines.