The basic formula for calculating area is Length times Width (LxW). If you are estimating the area for a rectangle you’ll always use LxW. If you are calculating the area for a square you can multiply the length of one Side times itself, or (S2).
The illustration above shows a room 12′ wide by 20′ long.
Area calculated as:
L X W = AREA
20 X 12 = 240 SQUARE FEET
When calculating the area for a structure with multiple sections, like an L-shaped home, divide the structure into two sections, then calculate the area for each section and add them together.
For example, in the L-shaped structure above the two sections have been divided to calculate the total area. Section one is 28 X 48. Section two is 20 X 16. The area calculation is:
SECTION ONE 28 X 48 = 1344 SQFT
SECTION TWO 20 X 16 = 320 SQFT
TOTAL = 1664 SQFT
When a structure has multiple ells or sections you can use a calculator with the memory feature to calculate the total square footage. First, divide the structure into logical square or rectangular sections. Then calculate the square foot area for each section, adding the calculation for each into memory plus on the calculator as you go.